Lumen-traveling biological interface device

ABSTRACT

Lumen-traveling biological interface devices and associated methods and systems are described. Lumen-traveling biological interface devices capable of traveling within a body lumen may include a propelling mechanism to produce movement of the lumen-traveling device within the lumen, electrodes or other electromagnetic transducers for detecting biological signals and electrodes, coils or other electromagnetic transducers for delivering electromagnetic stimuli to stimulus responsive tissues. Lumen-traveling biological interface devices may also include additional components such as sensors, an active portion, and/or control circuitry.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is related to and claims the benefit of theearliest available effective filing date(s) from the following listedapplication(s) (the “Related Applications”) (e.g., claims earliestavailable priority dates for other than provisional patent applicationsor claims benefits under 35 USC § 119(e) for provisional patentapplications, for any and all parent, grandparent, great-grandparent,etc. applications of the Related Application(s)).

RELATED APPLICATIONS

-   -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 10/949,186, entitled A CILIATED        STENT-LIKE SYSTEM, naming Richa Wilson, Victoria Y. H. Wood, W.        Daniel Hillis, Clarence T. Tegreene, Muriel Y. Ishikawa, and        Lowell L. Wood, Jr. as inventors, filed 24 Sep. 2004, which is        currently co-pending, or is an application of which a currently        co-pending application is entitled to the benefit of the filing        date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 10/827,576, entitled A SYSTEM FOR        PERFUSION MANAGEMENT, naming Lowell L. Wood, Jr. as inventor,        filed 19 Apr. 2004, which is currently co-pending, or is an        application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 10/827,578, entitled A SYSTEM WITH A        SENSOR FOR PERFUSION MANAGEMENT, naming Lowell L. Wood, Jr. as        inventor, filed 19 Apr. 2004, which is currently co-pending, or        is an application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 10/827,572, entitled A SYSTEM WITH A        RESERVOIR FOR PERFUSION MANAGEMENT, naming Lowell L. Wood, Jr.        as inventor, filed 19 Apr. 2004, which is currently co-pending,        or is an application of which a currently co-pending application        is entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 10/827,390, entitled A TELESCOPING        PERFUSION MANAGEMENT SYSTEM, naming Lowell L. Wood, Jr. as        inventor, filed 19 Apr. 2004, which is currently co-pending, or        is an application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 11/403,230, entitled        LUMENALLY-ACTIVE DEVICE, naming Bran Ferren, W. Daniel Hillis,        Roderick A. Hyde, Muriel Y. Ishikawa, Edward K. Y. Jung,        Nathan P. Myhrvold, Elizabeth A. Sweeney, Clarence T. Tegreene,        Richa Wilson, Lowell L. Wood, Jr. and Victoria Y. H. Wood as        inventors, filed 12 Apr. 2006, which is currently co-pending, or        is an application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 11/417,898, entitled CONTROLLABLE        RELEASE NASAL SYSTEM, naming W. Daniel Hillis, Roderick A. Hyde,        Muriel Y. Ishikawa, Elizabeth A. Sweeney, Clarence T. Tegreene,        Richa Wilson, Lowell L. Wood, Jr. and Victoria Y. H. Wood as        inventors, filed 4 May 2006, which is currently co-pending, or        is an application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 11/478,368, entitled        LUMENALLY-ACTIVE DEVICE, naming Bran Ferren, W. Daniel Hillis,        Roderick A. Hyde, Muriel Y. Ishikawa, Edward K. Y. Jung,        Nathan P. Myhrvold, Elizabeth A. Sweeney, Clarence T. Tegreene,        Richa Wilson, Lowell L. Wood, Jr. and Victoria Y. H. Wood, as        inventors, filed 28 Jun. 2006, which is currently co-pending, or        is an application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 11/485,619, entitled CONTROLLABLE        RELEASE NASAL SYSTEM, naming W. Daniel Hillis, Roderick A. Hyde,        Muriel Y. Ishikawa, Elizabeth A. Sweeney, Clarence T. Tegreene,        Richa Wilson, Lowell L. Wood, Jr. and Victoria Y. H. Wood as        inventors, filed 11 Jul. 2006, which is currently co-pending, or        is an application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 11/645,357, entitled LUMEN-TRAVELING        DEVICE, naming Bran Ferren, W. Daniel Hillis, Roderick A. Hyde,        Muriel Y. Ishikawa, Edward K. Y. Jung, Eric C. Leuthardt,        Nathan P. Myhrvold, Elizabeth A. Sweeney, Clarence T. Tegreene,        Lowell L. Wood, Jr. and Victoria Y. H. Wood as inventors, filed        21 Dec. 2006, which is currently co-pending, or is an        application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 11/645,358, entitled LUMEN-TRAVELING        DEVICE, naming Bran Ferren, W. Daniel Hillis, Roderick A. Hyde,        Muriel Y. Ishikawa, Edward K. Y. Jung, Eric C. Leuthardt,        Nathan P. Myhrvold, Elizabeth A. Sweeney, Clarence T. Tegreene,        Lowell L. Wood, Jr. and Victoria Y. H. Wood as inventors, filed        21 Dec. 2006, which is currently co-pending, or is an        application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. 11/651,946, entitled LUMEN-TRAVELING        DELIVERY DEVICE, naming Bran Ferren, W. Daniel Hillis,        Roderick A. Hyde, Muriel Y. Ishikawa, Edward K. Y. Jung, Eric C.        Leuthardt, Nathan P. Myhrvold, Elizabeth A. Sweeney, Clarence T.        Tegreene, Lowell L. Wood, Jr. and Victoria Y. H. Wood as        inventors, filed 9 Jan. 2007, which is currently co-pending, or        is an application of which a currently co-pending application is        entitled to the benefit of the filing date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. ______, entitled LUMEN-TRAVELING        BIOLOGICAL INTERFACE DEVICE AND METHOD OF USE, naming Bran        Ferren, W. Daniel Hillis, Roderick A. Hyde, Muriel Y. Ishikawa,        Edward K. Y. Jung, Eric C. Leuthardt, Nathan P. Myhrvold,        Clarence T. Tegreene, Lowell L. Wood, Jr. and Victoria Y. H.        Wood as inventors, filed substantially herewith, which is        currently co-pending, or is an application of which a currently        co-pending application is entitled to the benefit of the filing        date.    -   For purposes of the USPTO extra-statutory requirements, the        present application constitutes a continuation-in-part of U.S.        patent application Ser. No. ______, entitled BIOELECTROMAGNETIC        INTERFACE SYSTEM, naming Bran Ferren, W. Daniel Hillis,        Roderick A. Hyde, Muriel Y. Ishikawa, Edward K. Y. Jung, Eric C.        Leuthardt, Nathan P. Myhrvold, Clarence T. Tegreene, Lowell L.        Wood, Jr. and Victoria Y. H. Wood as inventors, filed        substantially herewith, which is currently co-pending, or is an        application of which a currently co-pending application is        entitled to the benefit of the filing date.

The United States Patent Office (USPTO) has published a notice to theeffect that the USPTO's computer programs require that patent applicantsreference both a serial number and indicate whether an application is acontinuation or continuation-in-part. Stephen G. Kunin, Benefit ofPrior-Filed Application, USPTO Official Gazette Mar. 18, 2003, availableat http://www.uspto.gov/web/offices/com/sol/og/2003/week11/patbene.htm.The present applicant entity has provided above a specific reference tothe application(s) from which priority is being claimed as recited bystatute. Applicant entity understands that the statute is unambiguous inits specific reference language and does not require either a serialnumber or any characterization, such as “continuation” or“continuation-in-part,” for claiming priority to U.S. patentapplications. Notwithstanding the foregoing, applicant entityunderstands that the USPTO's computer programs have certain data entryrequirements, and hence applicant entity is designating the presentapplication as a continuation-in-part of its parent applications as setforth above, but expressly points out that such designations are not tobe construed in any way as any type of commentary and/or admission as towhether or not the present application contains any new matter inaddition to the matter of its parent application(s).

All subject matter of the Related Applications and of any and allparent, grandparent, great-grandparent, etc. applications of the RelatedApplications is incorporated herein by reference to the extent suchsubject matter is not inconsistent herewith.

BACKGROUND

Devices and systems have been developed for use in various body lumens,particularly in the cardiovascular system, digestive tract, andurogenital tract. Catheters are used for performing a variety ofsensing, material delivery or surgical tasks. Stents are implanted inblood vessels for the purpose of preventing stenosis or restenosis ofblood vessels. Capsules containing sensing and imaging instrumentationthat may be swallowed by a subject and which travel passively throughthe digestive tract have also been developed. Robotic devices intendedto move through the lower portion of the digestive tract under their ownpower are also under development.

SUMMARY

The present application describes devices, systems, and related methodsfor performing one or more actions or tasks with a lumen-travelingbiological interface device. Embodiments of devices capable of movingthrough a body lumen to a location and delivering a stimulus to orrecording a signal from biological tissue are disclosed.

In one aspect, a lumen-traveling device may include a propellingmechanism capable of producing directional movement of thelumen-traveling device through a body lumen; a steering mechanismcapable of modifying a direction of movement of the lumen-travelingdevice; at least one electromagnetic transducer configured for at leastone of producing an output signal representative of a bioelectromagneticsignal sensed from a target tissue or delivering an electromagneticstimulus to the target tissue; and at least one of a signal processingportion capable of processing the output signal from the electromagnetictransducer or a stimulus source capable of producing an electromagneticstimulus for delivery to the target tissue with the electromagnetictransducer.

In another aspect, a lumen traveling device may include a propellingmechanism capable of producing directional movement of thelumen-traveling device through a body lumen; a steering mechanismcapable of modifying a direction of movement of the lumen-travelingdevice; at least one electromagnetic transducer configured for at leastone of producing an output signal representative of a bioelectromagneticsignal sensed from a target tissue or delivering an electromagneticstimulus to the target tissue; at least one of a signal processingportion capable of processing the output signal from the electromagnetictransducer or a stimulus source capable of producing an electromagneticstimulus for delivery to the target tissue with the electromagnetictransducer; and a sensor capable of sensing a local condition andgenerating a sense signal.

In addition to the foregoing, other device and system aspects aredescribed in the claims, drawings, and text forming a part of thepresent disclosure.

In one aspect, a method of emplacing a bioelectromagnetic signal sensingdevice may include causing a self-propelling bioelectromagnetic signalsensing device to travel within a body tube tree of a subject toward atarget site; if a branch point including two or more branches within thebody tube tree is reached by the self-propelling bioelectromagneticsignal sensing device, causing the self-propelling bioelectromagneticsignal sensing device to enter a branch leading toward the target site;and causing the self-propelling bioelectromagnetic signal sensing deviceto stop traveling upon reaching the target site.

In addition to the foregoing, other method aspects are described in theclaims, drawings, and text forming a part of the present disclosure.

Various aspects of the operation of lumen-traveling biological interfacedevices may be performed under the control of hardware, software,firmware, or a combination thereof. In one or more aspects, relatedsystems include but are not limited to circuitry and/or programming foreffecting the herein-referenced method aspects; the circuitry and/orprogramming can be virtually any combination of hardware, software,and/or firmware configured to effect the herein-referenced methodaspects depending upon the design choices of the system designer.

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an illustration of an embodiment of a lumen-traveling device;

FIGS. 2A-2D are illustrations of several embodiments of lumen-travelingdevice structural elements;

FIGS. 3A-3C are illustrations of several embodiments of lumen-travelingdevice structural elements;

FIGS. 4A and 4B are illustrations of a device structure having avariable length and diameter;

FIGS. 5A-5F are cross-sectional views of a number of embodiments oflumen-traveling device structures;

FIG. 6 illustrates an embodiment of a lumen-traveling device including amotion-arresting portion;

FIGS. 7A-7D are illustrations of several embodiments of lumen-travelingdevice active portions;

FIGS. 8A and 8B are illustrations of several further embodiments oflumen-traveling device active portions;

FIGS. 9A and 9B illustrate a positioning mechanism of a lumen-travelingdevice;

FIGS. 10A-10H depict examples of flow-modulating elements;

FIG. 11 is a depiction of a lumen-traveling device including afluid-collection structure;

FIG. 12 is a depiction of a lumen-traveling device including a materialcollection structure;

FIG. 13 illustrates an embodiment of an active portion of alumen-traveling device;

FIG. 14 illustrates an embodiment of an active portion of alumen-traveling device;

FIG. 15 illustrates an embodiment of an active portion of alumen-traveling device;

FIG. 16 is an illustration of a device including stored deliverablematerial;

FIG. 17 is a cross-sectional view of an embodiment of a device includinga stored deliverable material and a barrier release mechanism;

FIG. 18 is a cross-sectional view of another embodiment of a deviceincluding a stored deliverable material and a barrier release mechanism;

FIGS. 19A and 19B are depictions of the release of a stored deliverablematerial from a reservoir via a rupturable barrier;

FIGS. 20A and 20B are depictions of the release of a stored deliverablematerial from a reservoir via a degradable barrier;

FIGS. 21A and 21B are depictions of the release of a stored deliverablematerial from a reservoir via a barrier having controllablepermeability;

FIG. 22 is a cross-sectional view of another embodiment of a deviceincluding a stored deliverable material;

FIGS. 23A and 23B are depictions of the release of a stored deliverablematerial from a carrier material;

FIG. 24 illustrates a lumen-traveling device including a device releasestructure;

FIGS. 25A and 25B illustrate lumen-traveling devices including deliveryand receiving structures;

FIG. 26A is an illustration of a lumen-traveling device including acutting tool;

FIG. 26B is a cross-sectional view of the lumen-traveling device of FIG.26A;

FIG. 27 is an illustration of a lumen-traveling device including ascraping tool;

FIG. 28 is an illustration of a lumen-traveling system that includes anexternal control portion;

FIGS. 29A-29E illustrate a propelling mechanism of a lumen-travelingdevice;

FIGS. 30A and 30B illustrate an example of a lumen-traveling deviceincluding expanding and extending structures;

FIG. 31 illustrates a propelling mechanism of a lumen-traveling device;

FIGS. 32A and 32B illustrate another embodiment of a propellingmechanism;

FIG. 33 illustrates another embodiment of a propelling mechanism;

FIG. 34 is a schematic diagram of a lumen-traveling device;

FIG. 35 is a schematic diagram of a lumen-traveling device including aremote portion;

FIG. 36 is flow diagram of a method implemented with a lumen-travelingdevice;

FIG. 37 is flow diagram of a further method implemented with alumen-traveling device;

FIG. 38 is flow diagram of a further method implemented with alumen-traveling device;

FIGS. 39A and 39B form a flow diagram showing several variants of amethod implemented with a lumen-traveling device;

FIGS. 40A-40F form a flow diagram showing further variants of a methodimplemented with a lumen-traveling device;

FIG. 41 is a block diagram of a lumen-traveling device system;

FIG. 42 is block diagram of an embodiment of logic for controlling alumen-traveling device;

FIG. 43 is a block diagram of a further embodiment of logic forcontrolling a lumen-traveling device;

FIG. 44 is flow diagram of a method of using a lumen-traveling device;

FIG. 45 is a flow diagram of a method of using a lumen-traveling device;

FIG. 46 is a flow diagram of a method of using a lumen-traveling device;

FIG. 47 is a flow diagram of a method of using a lumen-traveling device;

FIGS. 48A-48C illustrate an embodiment of a system including twolumen-traveling devices;

FIG. 49 is a flow diagram of a method of using a lumen-traveling device;

FIGS. 50A and 50B are longitudinal cross-sectional views of an exampleof the operation of a lumen-traveling device in a body lumen;

FIGS. 51A and 51B are longitudinal cross-sectional views of an exampleof the operation of a lumen-traveling device in a body lumen;

FIGS. 52A and 52B are longitudinal cross-sectional views of an exampleof the operation of a lumen-traveling device in a body lumen;

FIGS. 53A and 53B are longitudinal cross-sectional views of an exampleof the operation of a lumen-traveling device in a body lumen;

FIG. 54 is a schematic diagram of an embodiment of a lumen-travelingdevice;

FIG. 55 is a schematic diagram of an embodiment of a lumen-travelingdevice;

FIG. 56 is a schematic diagram of an embodiment of a lumen-travelingdevice;

FIG. 57 is a schematic diagram of an embodiment of a lumen-travelingdevice including a remote portion;

FIG. 58 is a flow diagram of a method of emplacing an electricalstimulation device;

FIG. 59 is a flow diagram showing variations of the method of FIG. 58;

FIG. 60 is a flow diagram showing variations of the method of FIG. 58;

FIG. 61 is a flow diagram showing variations of the method of FIG. 58;

FIG. 62 is a diagram showing variations of the method of FIG. 58;

FIG. 63 is a diagram showing variations of the method of FIG. 58;

FIG. 64 illustrates the delivery of a lumen-traveling device into thebody by injection;

FIG. 65 illustrates the release of a lumen-traveling device from acatheter;

FIG. 66 illustrates the delivery of multiple lumen-traveling devices byinjection;

FIGS. 67A and 67B contain a flow diagram showing still furthervariations of the method of FIG. 58;

FIG. 68 illustrates delivery of a stimulus by a lumen-traveling devicebased upon a sensed signal;

FIG. 69 is a flow diagram of a further variation of the method of FIG.58;

FIG. 70 is a flow diagram of an extension of the method of FIG. 58 toinclude emplacement of at least one additional self-propellingelectromagnetic stimulation device;

FIG. 71 is a flow diagram of an extension of the method of FIG. 58;

FIG. 72 illustrates the use of multiple stimulation or recording devicespositioned around a target tissue;

FIGS. 73A, 73B and 73C illustrate the emplacement of abioelectromagnetic interface device at a target site in a body lumenwith a lumen-traveling device;

FIG. 74 is a flow diagram of a method of configuring abioelectromagnetic interface system;

FIG. 75 is a flow diagram showing variations of the method of FIG. 74;

FIG. 76 is a flow diagram showing variations of the method of FIG. 74;

FIG. 77 is a flow diagram of a method of emplacing a bioelectromagneticinterface system;

FIGS. 78A-78B illustrate the introduction of a plurality ofbioelectromagnetic interface devices simultaneously;

FIG. 79 illustrates the use of multiple stimulation or recording devicespositioned within a target tissue;

FIG. 80 is a flow diagram showing variants of the method of FIG. 77;

FIG. 81 is a flow diagram showing further variants of the method of FIG.77;

FIG. 82 is a flow diagram showing further variants of the method of FIG.77;

FIG. 81 is a flow diagram showing further variants of the method of FIG.77;

FIG. 84 is a flow diagram showing further variants of the method of FIG.77;

FIG. 85 is a flow diagram of a method of emplacing a neural stimulationdevice;

FIG. 86 is a flow diagram showing several variants of the method of FIG.85;

FIG. 87 is a flow diagram showing further variants of the method of FIG.85;

FIG. 88 is a flow diagram showing further variants of the method of FIG.85;

FIG. 89 is a diagram showing still further variants of the method ofFIG. 85;

FIG. 90 is a flow diagram of a method of emplacing a bioelectromagneticsignal sensing device;

FIG. 91 is a flow diagram showing several variations of the method ofFIG. 90;

FIG. 92 is a flow diagram showing further variations of the method ofFIG. 90;

FIG. 93 is a flow diagram showing further variations of the method ofFIG. 90;

FIG. 94 is a flow diagram of a method of emplacing a cardiac stimulationdevice;

FIG. 95 is a flow diagram showing several variants of the method of FIG.94; and

FIG. 96 is a flow diagram showing several additional variants of themethod of FIG. 94.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings, which form a part hereof In the drawings, similarsymbols typically identify similar components, unless context dictatesotherwise. The illustrative embodiments described in the detaileddescription, drawings, and claims are not meant to be limiting. Otherembodiments may be utilized, and other changes may be made, withoutdeparting from the spirit or scope of the subject matter presented here.

A lumen-traveling device is an example of a lumenally active device.Lumenally active devices, and related methods and systems, are describedin U.S. patent application Ser. No. 11/403,230, entitled “LumenallyActive Device,” filed Apr. 12, 2006, which is incorporated herein byreference. U.S. patent application Ser. No. 11/403,230 describes alumenally-active system that may include a structural element configuredto fit within at least a portion of a body lumen, the structural elementincluding a lumen-wall-engaging portion and a fluid-contacting portionconfigured to contact fluid within the body lumen; a sensor capable ofdetecting a condition of interest in the fluid; response initiationcircuitry operatively connected to the sensor and configured to generatea response initiation signal upon detection of the condition of interestin the fluid by the sensor; and an active portion operatively connectedto the response initiation circuitry and capable of producing a responseupon receipt of the response initiation signal.

As illustrated in FIG. 1, an embodiment of a lumen-traveling device 10may include a structural element 12 configured to fit within at least aportion of a body lumen 14. The structural element 12 may include alumen-wall-engaging portion 16 and a fluid-contacting portion 18configured to contact fluid within the body lumen. Lumen-travelingdevice 10 may also include a propelling mechanism 20 capable ofproducing movement of the structural element 12 through a body lumen 14in which the structural element is deployed, a sensor 22 capable ofdetecting a condition of interest in the body lumen, response initiationcircuitry 24 operatively connected to the sensor 22 and configured togenerate a response initiation signal upon detection of a condition ofinterest in the body lumen (e.g., plaque 30); and an active portion 26operatively connected to the response initiation circuitry and capableof producing a response upon receipt of the response initiation signal.Body lumen 14 is defined by wall portions 28, which may be the walls ofa blood vessel or other lumen-containing structure within the body of anorganism. In this example, a body fluid flows through lumen 14 in thedirection indicated by the arrow. Fluid flows through the centralopening 32 of structural element 12, with the interior surface ofstructural element 12 forming fluid-contacting portion 18. In theembodiment of FIG. 1, sensor 22 and active portion 26 may be located ata fluid-contacting portion 18. Lumen-wall-engaging portions 16 may be,for example, rotating wheels, which function to frictionally engage wallportions 28, and which may also, in combination with a rotary motor 20,function as a propelling mechanism 34 to move lumen-traveling device 10through body lumen 14. In other embodiments of lumenally travelingdevices, other structures and methods for engaging the lumen wall and/orpropelling the device through the lumen may be employed.

Embodiments of a lumen-traveling device or system may be configured foruse in (e.g., configured to fit within) body lumens of an organismincluding, for example, the respiratory tract, the cardiovascular system(e.g., a blood vessel), a portion of a CSF-space (cerebro-spinal fluidspace) of the nervous system (e.g., the spinal canal, the ventricles ofthe brain, the sub-arachnoid space, etc.), a portion of the urinarytract (for example a ureter), a portion of the lymphatic system, aportion of the abdominal cavity, a portion of the thoracic cavity, aportion of the digestive tract, a portion of a reproductive tract,either the female reproductive tract (e.g., a lumen of a fallopian tube)or the male reproductive tract (including various lumens including butnot limited to the epididymis, vas deferens or ductul deferens, efferentduct, ampulla, seminal duct, ejaculatory duct, or urethra), the biliarytract, a nostril or nasal cavity, the oral cavity, the digestive tract,the tear ducts, or a glandular system. Other body lumens may be found inthe auditory or visual system, or in interconnections thereof e.g., theEustachian tubes. Some of the devices and systems described herein maybe used in body lumens through which fluid flows, but it is not intendedthat such devices or systems are limited to use in tubularlumen-containing structures containing moving fluid; in someapplications a lumen-traveling device may be used in a body lumencontaining relatively unmoving, or intermittently moving fluid.

The term “body tube tree”, as used herein, refers to a body lumen havinga branching structure, i.e., that it includes at least one branch pointwhere a first region of a lumen splits into two or more branches, orwhere a side lumen branches off from a main lumen. “Body tube tree” isnot intended to convey any particular structure, configuration, level ororganization, or level of complexity, beyond that indicated above.Examples of body tube trees include, but are not limited, thecardiovascular system, the respiratory system, and the CSF-space, forexample.

Also included within the scope of the term “body lumen” are man-madelumens within the body, including vascular catheters, spinal fluidshunts, vascular grafts, bowel re-anastomoses, bypass grafts, indwellingstents of various types (e.g., vascular, gastrointestinal, tracheal,respiratory, ureteral, genitourinary, etc.) and surgically createdfistulas.

The term fluid, as used herein, may refer to liquids, gases, and othercompositions, mixtures, or materials exhibiting fluid behavior. Thefluid within a body lumen may include a liquid, or a gas or gaseousmixtures. As used herein, the term fluid may encompass liquids, gases,or mixtures thereof that also include solid particles in a fluidcarrier. Liquids may include mixtures of two or more different liquids,solutions, slurries, or suspensions. Body fluids may include componentssuch as, for example, cells, cellular fractions or components,collections or aggregations of cells, bacterial, viral or fungalspecies, ions, molecules, gas bubbles, dissolved gas, suspendedparticles, or a variety of other materials that may be present in thebody fluid. Body fluid components may be materials that are normallypresent in the body fluid, materials that are naturally derived but notnormally present in the body fluid, or foreign materials that haveentered or been introduced to the body fluid (including but not limitedto pathogens, toxins, pollutants, or medications, for example). Examplesof liquids present within body lumens include blood, lymph, serum,urine, semen, digestive fluids, tears, saliva, mucous, cerebro-spinalfluid, intestinal contents, bile, epithelial exudate, or esophagealcontents. Liquids present within body lumens may include synthetic orintroduced liquids, such as blood substitutes, or drug, nutrient, orsaline solutions. Fluids may include liquids containing dissolved gasesor gas bubbles, or gases containing fine liquid droplets or solidparticles. Gases or gaseous mixtures found within body lumens mayinclude inhaled and exhaled air, e.g. in the nasal or respiratory tract,or intestinal gases.

A lumen-traveling device may be configured to fit within a particularlumen through appropriate selection of device dimensions, materialproperties, and propelling mechanism. Configuration aspects may includesize, shape, rigidity/flexibility, porosity, and biocompatibility, amongothers, which may depend on both the materials and construction of thedevice. Dimensions of a lumen-traveling device may be selected so thatthe device will be small enough to fit within the smallest expecteddimension of the lumen of interest. A material that is bothbiocompatible and sufficiently durable for use in the lumen of choicemay be selected based on standards well known to those of skill in theart. Wherever a lumen-traveling device or system is to be used, thedimensions and mechanical properties (e.g., rigidity) of thelumen-traveling system, and particularly of the structural element ofthe lumen-traveling system, may be selected for compatibility with thelocation of use, in order to provide for reliable positioning of thedevice and to prevent damage to the lumen-containing structure includingthe body lumen. The propelling mechanism may be selected for the typeand nature of the lumen to be traveled. A lumen having a relativelyuniform cross-section (height and/or width) over the length to betraveled may be traversed by most propelling mechanisms. A lumen thatvaries significantly in cross-section over the length to be traveled maypose a challenge for some propelling mechanisms that engage the lumenwall on all sides, but a lumen-traveling device that walks or rollsalong one side of a lumen, or employs more than one mode of propulsion,may adapt well to changes in lumen cross-section. A lumen-travelingdevice that is capable of altering its dimensions (e.g. changing inlength and diameter) may also be of utility in some applications. Forexample, see U.S. Patent Application 2005/0177223, which is incorporatedherein by reference in its entirety. However, in many cases it may bepossible to design a lumen-traveling device of fixed dimension suitedfor a particular application, or provide a set of lumen-travelingdevices in several sizes, from which the best size can be selected for aparticular application or particular patient, to account for variabilityin lumen dimensions between individual patients. The lumen-travelingdevice may include a structural element carrying at least one of thepropelling mechanism, motion control circuitry, sensor, responseinitiation circuitry or active portion. Various materials may be used inthe construction of the structural element. For example, the structuralelement may include a self-expanding material, a resilient material, ora mesh-like material. Flexibility may also be conferred by configurationas well as material: for example, the structural element may include aslotted structure. The structural element may include a biocompatiblematerial, as noted above, and may include a bioactive component (such asa drug-releasing coating or bioactive material attached to orincorporated into the structural element).

FIGS. 2A-2D depict a number of possible configurations for structuralelements of lumen-traveling devices for use in body lumens. In someembodiments, the structural element may be a substantially tubularstructure. The structural element may include one or multiple lumens influid communication with the body lumen. In some embodiments, thestructural element may have an adjustable diameter. Structural elementsmay have the form of a short cylinder 50, as shown in FIG. 2A; anannulus 52, as shown in FIG. 2B; a cylinder 54, as shown in FIG. 2C; ora spiral 56, as shown in FIG. 2D. A spiral structure is disclosed, forexample, in Bezrouk et al, “Temperature Characteristics of NitinolSpiral Stents”; Scripta Medica (BRNO); bearing dates of August 2005,October 2005; pp. 219-226; Vol. 78, No. 4, which is incorporated hereinby reference in its entirety. Elongated forms such as cylinder 54 orspiral 56 may be suitable for use in tubular lumen-containing structuressuch as, for example, blood vessels.

Structural elements may be formed from various materials, includingmetals, polymers, fabrics, and various composite materials, includingones of either inorganic or organic character, the latter includingmaterials of both biologic and abiologic origin, selected to providesuitable biocompatibility and mechanical properties. In these, and otherexamples of structural elements, it is contemplated that additionalcomponents, such as sensors, circuitry, and propelling mechanisms, forexample, will be attached or connected to, manufactured on, or formedintegrally with the structural element, but such additional componentsare not illustrated in these figures.

In some embodiments, the structural element may include a self-expandingmaterial, or a resilient material. In some embodiments, the form as wellas the material of the structural element may contribute to theexpanding or flexing properties of the structural element. For example,the structural element may be formed from or include a mesh-likematerial or a slotted structure.

As shown in FIGS. 3A-3C, the basic form of a structural element may besubject to different variations, e.g., by perforations, as shown instructural element 60 in FIG. 3A; a mesh structure, as shown instructural element 62 in FIG. 3B; or the inclusion of one or more slots64 in structural element 66 in FIG. 3C. Slot 64 runs along the entirelength of structural element 66; in other embodiments, one or more slots(or mesh or perforations) may be present in only a portion of thestructural element. By using spiral, mesh, or slotted structuralelements (as in FIGS. 2D, 3B, and 3C) formed from resilient material,elastic, springy or self-expanding/self-contracting structural elementsmay be formed. A self-expanding or self-contracting structural elementmay facilitate positioning of the structural element within a body lumenof an organism. In some embodiments, flexible material having adjustablediameter, taper, and length properties may be used. For example, somematerials may change from a longer, narrower configuration 70 as shownin FIG. 4A, to a shorter, wider configuration 72 as shown in FIG. 4B, ormay taper over their length. Structural elements that may exhibit thistype of expansion/contraction property may include mesh structuresformed of various metals or plastics, and some polymeric materials, forexample. Examples of possible shape change materials are described in“Agile new plastics change shape with heat”; MIT News Office; Nov. 20,2006; pp. 1-4; Massachusetts Institute of Technology; printed on Nov.22, 2006; located athttp://web.mit.edu/newsoffice/2006/triple-shape.html; “Agile newplastics change shape with heat”; MIT Tech Talk; Nov. 22, 2006; p. 5 (1page); and SHAHINPOOR, MOHSEN; KIM, KWANG J. (“Ionic polymer-metalcomposites: IV. Industrial and medical applications; Smart Materials andStructures; 2005; pp. 197-214; Vol. 14; Institute of PhysicsPublishing), all of which are incorporated herein by reference in theirentirety.

The exemplary embodiments depicted in FIGS. 2A-2C, 3A-3C, and 4A and 4Bare substantially cylindrical, and hollow and tubular in configuration,with a single central opening. Thus, the exterior of the cylindricalstructural element may contact and engage the wall of the body lumen,and the interior of the structural element (within the single centralopening) may form a fluid-contacting portion of the structural element.Lumen-traveling devices according to various embodiments are not limitedto cylindrical structural elements having a single central opening,however. Alternatively, a structural element may be configured tocontact and move along a portion of a wall of a body lumen, contactingor engaging the lumen wall over a portion of its cross-section (asopposed to contacting the lumen wall along its entire cross-section)without obstructing the movement of fluid within the body lumen. Such anembodiment may be approximately hemi-spherical or hemi-elliptoid, with across-section as depicted in FIG. 5A. Other embodiments may be pill- orcapsule-shaped, adapted to move through a central portion of a bodylumen.

FIGS. 5A through 5F depict a variety of cross-sectional configurationsfor structural elements of lumen-traveling devices. In FIG. 5A, alumen-traveling device 100 is positioned in lumen 102 oflumen-containing structure 104. In this embodiment, fluid-contactingportion 106 may be the surface of structural element 100 that faceslumen 102, while the lumen-wall-engaging portion 108 may include a layerof tissue adhesive on surface 110 of structural element 100. Tissueadhesives may be released from the lumen-traveling device when it hasreached its destination. Lumen-traveling device 100 may be approximatelyhemi-spherical or hemi-ovoid. Lumen-wall-engaging portion 108 may have acurvature that corresponds approximately to the curvature of the lumen.

FIG. 5B depicts in cross-section a further embodiment of a structuralelement 150 in lumen 152 of lumen-containing structure 154. Structuralelement 150 includes multiple openings 156, each of which includes aninterior surface 158 that forms a fluid-contacting portion. Structuralelement 150 may include one or more hook or claw-like structures 160that serve as lumen-wall-engaging portions that maintain structuralelement 150 in position with respect to lumen-containing structure 154.

FIG. 5C depicts in cross-section an embodiment of a structural element200 in lumen 202 of lumen-containing structure 204. Structural element200 includes a large central opening 206 and multiple surroundingopenings 208. The interior surface of each opening 206 or 208 serves asa fluid-contacting portion, while projections 210 function aslumen-wall-engaging portions, which may engage frictionally or mayproject slightly into the interior of the wall of lumen-containingstructure 204.

FIG. 5D depicts a further embodiment in which structural element 250 hasa substantially oval cross-section and includes a slot 252.Lumen-containing structure 254 may be generally oval in cross section,or may be flexible enough to be deformed to the shape of structuralelement 250. Structural element 250 may be a compressed spring-likestructure that produces outward forces as indicated by the black arrows,so that end portions 256 of structural element 250 thus press againstand engage the lumen wall. Interior surface 258 of structural element250 serves as the fluid-contacting portion of structural element 250.

FIG. 5E is a cross-sectional view of a structural element 300 in alumen-containing structure 302. Structural element 300 includes multipleprojecting arms 304 which contact lumen wall 306 of lumen-containingstructure 302, and function as lumen-wall-engaging portions. Innersurfaces 308 of arms 304 function as fluid-contacting portions ofstructural element 300.

FIG. 5F depicts (in cross-section) another example of a structuralelement 350 positioned within a lumen-containing structure 352.Structural element 350 includes two openings 354. The interior surfaces356 of openings 354 function as fluid-contacting portions, while theouter surface 358 of structural element 350 serves as alumen-wall-engaging portion.

The structural elements depicted in FIGS. 1-5 are intended to serve asexamples, and are in no way limiting. The choice of structural elementsize and configuration appropriate for a particular body lumen may beselected by a person of skill in the art. Structural elements may beconstructed by a variety of manufacturing methods, from a variety ofmaterials. Appropriate materials may include metals, ceramics, polymers,and composite materials having suitable biocompatibility,sterilizability, mechanical, and physical properties, as will be knownto those of skill in the art. Examples of materials and selectioncriteria are described, for example, in The Biomedical EngineeringHandbook, Second Edition, Volume I, J. D. Bronzino, Ed., Copyright 2000,CRC Press LLC, pp. IV-1-43-31. Manufacturing techniques may includeinjection molding, extrusion, die-cutting, rapid-prototyping,self-assembly, etc., and will depend on the choice of material anddevice size and configuration. Sensing portions, active portions, andpropelling mechanisms or structures of the lumen-traveling device aswell as associated circuitry (not depicted in FIGS. 2-5) may befabricated on the structural element using various microfabricationand/or MEMS techniques, or may be constructed separately andsubsequently assembled to the structural element, as one or moredistinct components. Examples of microfabrication techniques include,for example, those disclosed in U.S. Patent Applications 2005/0221529,2005/0121411, 2005/0126916, and NYITRAI, ZSOLT; ILLYEFALVI-VITÉZ, ZSOLT;PINKOLA, JÁNOS; “Preparing Stents with Masking & Etching Technology”;26^(th) International Spring Seminar on Electronics Technology; bearingdates of May 8, 2003-May 11, 2003 and 2003; pp. 321-324; IEEE, all ofwhich are incorporated by reference in their entirety.

According to an embodiment as shown in FIG. 6, a lumen-traveling device400 may include a motion-arresting portion 402; a fluid-contactingportion 404 configured to contact fluid within a body lumen and to atleast intermittently permit flow of fluid through the body lumen; apropelling mechanism 406 capable of producing movement of thelumen-traveling device through a body lumen in which the lumen-travelingdevice is deployed; motion control circuitry 408 carried at least inpart by said lumen-traveling device and configured to control thepropelling mechanism 406 to control movement of the lumen-travelingdevice 400 through the body lumen; a sensor 410 capable of detecting acondition of interest in the body lumen and generating a sense signal412 indicating detection of the condition of interest; responseinitiation circuitry 414 operatively connected to the sensor andconfigured to generate a response initiation signal 416 upon receipt ofthe sense signal indicating detection of a condition of interest in thebody lumen; and an active portion 418 operatively connected to theresponse initiation circuitry and capable of producing a response uponreceipt of the response initiation signal. In some embodiments, thecondition of interest may be a local condition of interest (e.g. acondition related to the presence of injured or diseased tissue, ananatomical feature, etc.).

The motion control circuitry may be operatively connected to the sensorand configured to control the propelling mechanism at least in part inresponse to receipt of the sense signal indicating detection of thecondition of interest in the body lumen.

The motion-arresting portion may take various forms, including, forexample, an anchor capable of attaching at least temporarily to a wallof the lumen, as shown in FIG. 6; at least one hook or claw, e.g. asdepicted in FIG. 5B; at least one adhesive material or glue, as shown inFIG. 5A; a brake to oppose the action of the propelling mechanism, or ashutoff for the propelling mechanism. In some embodiments, themotion-arresting portion may include a reversal mechanism for thepropelling mechanism, in that to arrest motion it may be necessary toprovide sufficient propulsion in the reverse direction to oppose a flowof fluid through the body lumen. The motion-arresting portion may be apart of, or associated with, the propelling mechanism (e.g. a shutofffor the propelling mechanism) or it may be a separate mechanism(adhesive, hook- or claw-like structure, anchor, etc.).

The lumen-traveling device may include an active portion capable ofproducing a response upon receipt of the response initiation signal. Alumen-traveling device may include a single active portion or multipleactive portions, which may be of the same or different types. Activeportions may perform related or complementary functions. A number ofdifferent types of active portion may be used in embodiments of thelumen-traveling device; a lumen-traveling device may include one or moreactive portions, and each active portion may perform one or moreactions.

FIGS. 7-27 provide examples of different active portions which may beincluded in a lumen-traveling device. Some active portions may be mostsuitable for use in a lumen-traveling device while it is moving, andsome active portions may be most suitable for use by a lumen-travelingdevice that is at rest within a body lumen. Many of the examples ofactive portions described herein may be adapted for use under eithercircumstance.

The active portion may include a heating element 450 as depicted in FIG.7A, operatively coupled to the response initiation circuitry 451 andconfigured to produce heating in response to receipt of the responseinitiation signal. The heating element may be a resistive element thatproduces heat when current is passed through it, or it may be amagnetically active material that produces heat upon exposure to anelectromagnetic field. Examples of magnetically active materials includepermanently magnetizable materials, ferromagnetic materials such asiron, nickel, cobalt, and alloys thereof, ferrimagnetic materials suchas magnetite, ferrous materials, ferric materials, diamagnetic materialssuch as quartz, paramagnetic materials such as silicate or sulfide, andantiferromagnetic materials such as canted antiferromagnetic materialswhich behave similarly to ferromagnetic materials; examples ofelectrically active materials include ferroelectrics, piezoelectrics anddielectrics. In some embodiments, heat may be generated through anexothermic chemical reaction. U.S. Patent Applications 2002/0147480 and2005/0149170, provide examples of heating and/or cooling mechanisms andstructures, and are incorporated herein by reference.

Alternatively, the active portion may include a cooling element 452 asdepicted in FIG. 7B, operatively coupled to the response initiationcircuitry 453 and configured to produce cooling in response to receiptof the response initiation signal. Cooling may be produced by a numberof mechanisms and/or structures. For example, cooling may be produced byan endothermic reaction (such as the mixing of ammonium nitrate andwater) initiated by opening of a valve or actuation of a container inresponse to a control signal. Other methods and/or mechanisms ofproducing cooling may include, but are not limited to, thermoelectric(Peltier Effect) and liquid-gas-vaporization (Joule-Thomson) devices.

In some embodiments, the active portion may include an electromagneticradiation source 454 as depicted in FIG. 7C, operatively coupled to theresponse initiation circuitry 455 and configured to emit electromagneticradiation in response to receipt of the response initiation signal.Electromagnetic radiation sources may include light sources, forexample, such as light emitting diodes and laser diodes, or sources ofother frequencies of electromagnetic energy or radiation, radio waves,microwaves, ultraviolet rays, infra-red rays, optical rays, terahertzbeams, and the like.

The active portion may include an acoustic energy source 456 (e.g. apiezoelectric element) as depicted in FIG. 7D, operatively coupled tothe response initiation circuitry 457 and configured to emit acousticenergy in response to receipt of the response initiation signal. Anacoustic energy source may generate pressure pulses of variousfrequencies, including auditory frequencies, subsonic frequencies, andultrasonic frequencies. A microscale acoustic transducer may beconstructed, for example, in U.S. Pat. No. 5,569,968, which isincorporated herein by reference.

The active portion may include a pressure source operatively coupled tothe response initiation circuitry and configured to apply pressure tothe body lumen in response to receipt of the response initiation signal.Applied pressure may be positive pressure (e.g., to form a pressure fitof the device with the lumen wall, as described above, or to applypressure to a particular location, e.g. to stop bleeding) or negativepressure (e.g., a vacuum, to adhere a portion of the lumen wall to thelumen-traveling device, for example to seal off a leak or aneurysm, orto position the device, as described previously). Pressure applied to abody lumen may influence one or both of the lumen walls or the contentsof the lumen; in some cases application of pressure to a body lumen mayincrease (or decrease) the pressure in a fluid (gas or liquid) withinthe body lumen. A pressure source may include materials that expandthrough absorption of water or other materials, expand or contract dueto generation or consumption of gas, or change conformation by chemicalreactions or temperature changes, electrically-engendered Maxwellstresses, osmotic stress-generators, etc. FIG. 8A depicts a negativepressure source 460 capable of applying negative pressure (in thisexample, substantially radially-inward force) to lumen walls 461, whileFIG. 8B depicts a positive pressure (expanding or expansion) source 462,capable of applying positive pressure (in this example, a substantiallyradially-outward force) to lumen walls 461.

Application of negative pressure to draw the lumen walls inward to forma seal with the lumen-traveling device, as depicted in FIG. 8A, may beuseful for repairing or compensating for an aneurysm or other structuraldamage or imperfection to a lumen wall. Expansion and/or application ofpositive pressure by the lumen-traveling device may function to open aconstricted lumen or secure a lumen-traveling device in place within alumen, as depicted in FIG. 8B. Expansion of all or a portion of thelumen-traveling device may include expansion of a structural element ora portion thereof, which may be produced by inflation of one or morechambers with liquid or gas, or expansion or change in configuration ofa shape-change material, bimetallic structure, etc.

The active portion may include a positioning element operatively coupledto the response initiation circuitry and configured to secure thelumen-traveling device into position within the body lumen in responseto receipt of the response initiation signal. A positioning element maybe a hook or claw-like structure that may penetrate into or catch on thesurface of the lumen wall, as in FIG. 5B, an expanding element thatcauses the lumen-traveling device to form a pressure-fit with the lumen,as in FIG. 8B, an adhesive material or glue, as in FIG. 5A, or otherstructure or material that may engage the lumen wall. A positioningelement may also include a suction (negative pressure) generatingmechanism that causes lumen-traveling device to adhere to the walls ofthe body lumen by suction, as depicted in FIG. 8A, for example. Claw orhook-like structures may be fixed or movable. Movable structures mayinclude mechanical elements and/or materials that change shape orrigidity in response to temperature, electric field, magnetic field, orvarious other control signals. As an example, FIGS. 9A and 9B depict alumen-traveling device 554 that includes positioning elements 556.Positioning elements such as positioning element 556 may be used asactive portions in some embodiments of the invention. FIG. 9B is a closeup view showing a portion 558 of lumen-traveling device 554, and detailof positioning element 556. Positioning element 556 is shown in anextended configuration (indicated by a solid outline) but may also beretracted (as indicated by the dashed outline and reference number 560).For example, positioning element 556 may change configuration onexposure to an electric current from current source 562 connected topositioning element 556 via circuitry 564. Positioning element 556 maybe a claw-like projection that may be moved or extended to cause it todig into a lumen wall to position lumen-traveling device 554 withrespect to a lumen wall. Positioning element 556 may cause thelumen-traveling device to be retained in a desired position within alumen for brief or extended periods of time. For example positioningelements may be extended to temporarily hold the lumen-traveling devicein place and subsequently retracted to permit the lumen-traveling deviceto continue moving through the lumen. Alternatively, the lumen-travelingdevice may move through the lumen until it reaches a location ofinterest, and then the positioning elements may be extendedsubstantially permanently to retain the lumen-traveling device at thelocation of interest substantially permanently. Various other types ofpositioning elements may be used, as well. For example, claws, clips,tensioning elements, expanding elements, and adhesives are all examplesof positioning elements that may be used to retain a lumen-travelingdevice in a location. Certain positioning elements may be suited toretaining the lumen-traveling device in a location for extended periods,while other positioning elements may be more suited to retaining thelumen-traveling device in a location only briefly.

The active portion may include a flow-modulating element operativelyconnected to the response initiation circuitry and configured tomodulate the flow of fluid through at least a portion of the body lumenin response to receipt of the response initiation signal. Aflow-modulating element may modulate the flow of fluid through the bodylumen to modify the amount of turbulence in the flow, the volume rate offlow, the fluid velocity, the direction of flow, or some other flowcharacteristic. A flow-modulating element may be, for example, a valve,a louver, a flow-directing element, a splitter or flow divider, afilter, a baffle, a channel restriction, a channel widening, or otherstructure capable of modifying the fluid flow according to principles offluid dynamics known in the art. FIG. 10A illustrates lumen-travelingdevice portion 600 including a first channel 602 and a second channel604, in which are located valves 606 and 608, respectively. Valve 606 isin the open position, allowing fluid flow as indicated by the arrow.Valve 608 is in the closed position, to block the flow of fluid. Valves606 and 608 may be any of various types of controllable valves ormicrovalves.

FIG. 10B illustrates a lumen-traveling device 610 including a louver612, positioned within lumen 614. Louver 612 may modify the flow offluid within lumen 614, e.g., by reducing turbulent flow or reducingflow velocity. Fluid may flow on either side of louver 612, as indicatedby the arrows.

FIG. 10C illustrates a lumen-traveling device 620 including aflow-directing element 622. Flow-directing element 622 may direct theflow of fluid within lumen 624, so that fluid tends to move toward aparticular portion of the lumen.

FIG. 10D depicts a portion 630 of a lumen-traveling device that includesa splitter (or flow divider) 632. Fluid may flow into main channel 634and be divided so that it flows into branch channels 636 and 638, whichmay lead to additional structures within a lumen-traveling device orwithin the body lumen (e.g., if the lumen-traveling device was used inthe vascular system, branch channels 636 and 638 could lead toparticular blood vessels branching off of a larger blood vessel in whichthe lumen-traveling device resided). A valve placed across main channelentrance 640, or across the entrance of one or both branch channels(e.g., at entrance 642 of branch channel 636) may be used to control theoperation of splitter 632.

FIG. 10E depicts a lumen-traveling device 650 including a filter 652, ina body lumen defined by lumen walls 654. Filter 652 may be formed ofscreen, mesh, fibers, a sintered material, or various other materials,selected to remove particles in a particular size range or havingparticular affinity or binding properties from the fluid flowing thoughthe filter.

FIG. 10F depicts a lumen-traveling device 660 that include a baffle 662for modifying the flow of fluid through the central opening 664 oflumen-traveling device 660. In some embodiments, e.g. as depicted inFIG. 10F, baffle 662 may be capable of rotating on axis 664 to move thebaffle in an out of the channel to provide controlled modulation offluid flow.

FIG. 10G depicts a lumen-traveling device portion 670 having a centralchannel 672 with a channel restriction 674. Channel restriction 674 maybe formed by a projecting portion 676 extending around the circumferenceof channel 672. Projecting portion 676 may be an expandable orinflatable structure, to provide a controllable channel restriction.

FIG. 10H depicts a lumen-traveling device portion 680 having a centralchannel 682 leading to a channel widening 684. Channel widening 684 maybe formed by retraction of an expandable or inflatable structure 686extending around the circumference of channel 682. Expandable orinflatable structure 686 is shown in retracted configuration 686 a (thusforming channel widening 684) and in expanded configuration 686 b, inwhich substantially no channel widening is formed. Expandable orinflatable structure 686 may be expanded to varying degrees to formvarying sizes of channel widenings.

In some embodiments, the active portion of a lumen-traveling device mayinclude a separator operatively connected to the response initiationcircuitry and configured to selectively remove specific components fromthe fluid in response to detection of the condition of interest. Aseparator may be, for example, a molecular sieve or mechanical filter(including, for example, screen, mesh, fiber, etc., as depicted in FIG.10E) having openings sized to allow passage of particles or structuresof a particular size or size range, or a chemical or biochemicalseparator based on binding affinity, charge, surface energy, etc. as iswell known to those in the art. For example, U.S. Patent Application2005/0126916, which is incorporated herein by reference, provides anexample of a microfabricated mesh. A separator may remove componentsthat are not desired from the fluid (e.g., because they are foreign,harmful, etc.) or it may remove components for the purpose of collectinga sample for analysis. Thus, in related embodiments the active portionmay include a sample collector. Either fluid or solid (e.g., tissue)samples may be collected or captured, depending on the type and/ordesign of the sample collector. Examples of sample collection structuresand mechanisms are provided in U.S. Pat. Nos. 6,436,120 and 6,712,835,and HANNA, DARRIN M.; OAKLEY, BARBARA A.; STRYKER, GABRIELLE A.; “Usinga System-on-a-Chip Implantable Device to Filter Circulating InfectedCells in Blood or Lymph”; IEEE Transactions on Nanobioscience; bearingdates of Jan. 25, 2003, March 2003; pp. 6-13; Vol. 2, No. 1; IEEE, allof which are incorporated herein by reference in their entirety. Anothermechanism for capturing a solid material is a grasper as disclosed inU.S. Pat. No. 6,679,893, which is incorporated herein by reference.

In some embodiments the active portion may include a fluid captureportion operatively coupled to the response initiation circuitry andconfigured to capture the detected material of interest. FIG. 11 depictsa device 700 including a fluid capture portion 706. Lumen-travelingdevice 700 includes sensor 702, response initiation circuitry 704, andfluid capture portion 706. Fluid enters fluid capture portion 706 viainlet 708. Fluid capture portion 706 may be a reservoir, for example,into which fluid is drawn by capillary action or by a negative pressuregenerated by a pump, for example. Captured fluid may be treated andreleased, or simply stored. In some applications, stored fluid may besubjected to analysis.

The sample collection portion may be a fluid capture portion configuredto passively collect a fluid and/or constituents thereof, includingcells or other biologics, within a matrix material, which might belocated on the exterior of the lumen-traveling device in someembodiments, or contained in a chamber (e.g., fluid capture portion 706in FIG. 11) in other embodiments. The matrix material may include anabsorbent such as cotton, cellulose, natural or artificial sponge, a gel(a natural gel such as agarose, a natural and/or synthetic polymer gel,a hydrogel), a colloid, a gum base such as acacia gum, or microparticles. The sample collection portion may include a lipid monolayer,lipid bilayer, liposome, dendrimer, ligand affinity resin withconjugated peptide or antibody, ionophore, hydrosol, sol-gel, xerogel,aerogel, smart gel, hydrocarbon gel, or ferrogel. Many types of poroushydrogels are known, such as those used in the wound dressing of U.S.Pat. No. 6,372,248, incorporated herein by reference in its entirety.Alternatively, the sample collector may include a synthetic or naturaladsorbent material such as a proteoglycan or charged polymer likepolylysine, of a type that promotes the adhesion of one or more fluidconstituent, e.g. a cell or protein. Other materials may includesemi-specific or non-specific adsorbers, such as silica (SiO₂) oralumina (Al₂O₃) gel or ion exchange resin, possibly as part of thematrix material. Further examples of materials for sample collection aredisclosed in U.S. Pat. Nos. 6,861,001 and 6,475,639, which areincorporated herein by reference. Alternatively or in addition, thesample collector may include one or more recognition elements of a typeable to recognize and/or specifically bind a constituent of the fluid.Such a recognition element might be a biologic, such as a staphylococcusprotein A complex, which generally binds immunoglobulins; a bindingpeptide or protein like an immunoglobulin; a DNA binding protein and/orgenetically engineered protein; a nucleic acid, perhaps an aptamer; acarbohydrate; a lipid; a conjugate; or a synthetic molecule like anartificial antibody or other mimetic. U.S. Pat. Nos. 6,255,361;5,804,563; 6,797,522; and 5,831,012 and U.S. Patent Application2004/0018508 provide examples of such mimetics and are incorporatedherein by reference in their entirety.

FIG. 12 depicts lumen-traveling device 750 including a sample collectionstructure 752 capable of collecting a solid sample 754, e.g. for biopsypurposed and/or for removal of damaged, diseases, or otherwise unwantedtissue. In the example depicted in FIG. 12, solid sample 754 is a solidmaterial found upon or immediately under the surface of thelumen-defining wall 756 (an arterial plaque, for example). Solid sample754 placed in storage reservoir 758 by sample collection structure 752.In a related alternative embodiment, a lumen-traveling device mayinclude a filter or selective binding region to remove materials fromfluid moving past or through the lumen-traveling device.

In some embodiments, the active portion may include a catalytic portionoperatively connected to the response initiation circuitry andconfigured to expose or activate a catalyst in response to receipt ofthe response initiation signal. Examples of catalysts include inorganiccatalysts such as metal surfaces, and organic catalysts such as enzymes.A surface having catalytic properties (such as a metal) or havingcatalytic material adhered or bound thereto may be exposed or activatedby directing the flow of fluid across, the surface, modifying a chemicalproperty of the surface, or removing a covering from the surface. Forexample, as shown in cross-section in FIG. 13, a lumen-traveling deviceportion 800 may include a channel divider 802 separating two channels804 and 806. Channel 806 includes catalytic material 808, which iscapable of catalyzing a reaction with one or more component of fluidflowing through channel 806, as indicated by the arrow. A movable gate810 on pivot 812 may block the flow of fluid into channel 804 whilepermitting the flow of fluid into channel 806 and across catalyticmaterial 808, or it may be repositioned to block the flow of fluid intochannel 806 while permitting the flow of fluid into channel 804. In someembodiments of a lumen-traveling device, the active portion may includea catalytic portion operatively connected to the response initiationcircuitry and configured to expose a catalytic surface to the fluid inresponse to detection of the condition of interest. The catalyticsurface may catalyze a reaction that modifies or destroys a material ofinterest, for example.

The active portion may include an electric field source, as depicted inFIG. 14, operatively connected to the response initiation circuitry andconfigured to apply an electric field to the fluid and/or lumen wall orsurrounding tissue in response to receipt of the response initiationsignal. For example, a lumen-traveling device 820, here shown contactingwall 822 of lumen 824, may include a first contact 826 and secondcontact 828 connected to source 830. Source 830 may be a capacitor orother charge storing device, to generate a static electric field, or itmay be current source capable of generating a dynamic electric field.

Alternatively, as shown in FIG. 15, an active portion may include amagnetic field source operatively connected to the response initiationcircuitry and configured to apply a magnetic field to the fluid and/orlumen wall or surrounding tissue in response to receipt of the responseinitiation signal. A lumen-traveling device 840 adjacent wall 842 oflumen 844 may include (for example) a coil 846 connected to currentsource 848. Current from current source 848 flowing through coil 846will produce a magnetic field as indicated in FIG. 15. The magneticfield source need not include a coil; as known to those of skill in theart, a magnetic field may be generated by current flowing throughvarious types of structures. Moreover, one or more fixed magnets may beincluded in a magnetic field source.

In some embodiments, the active portion of a lumen-traveling device mayinclude a material release structure operatively coupled to the responseinitiation circuitry and configured to release a material in response toreceipt of the response initiation signal. FIG. 16 depicts a deliverydevice 900 including a structural element 902, sensor 904, controlsignal generation circuitry 906, and release structure 908 includingrelease mechanism 910. Structural element 902 includes external surface912, configured to fit within a body lumen, and internal surface 914defining central opening 916, through which a fluid may flow. Uponsensing of a condition of interest in the fluid by sensor 904, controlsignal generation circuitry 906 may cause release of material frommaterial release structure 908 by activating release mechanism 910.Release mechanism 910 may include a variety of different types ofrelease mechanisms, including, for example, a controllable valve.Various types of valves and microvalves are known to those of skill inthe art, and may be used to regulate the release of material frommaterial release structure 908 in response to a control signal fromcontrol signal generation circuitry 906. Control signal generationcircuitry 906 may activate release mechanism 910 by supplying a deliverycontrol signal, which may be an electrical signal, for example. In someembodiments, other types of delivery control signals, including magneticsignals, optical signals, acoustic signals, or other types of signalsmay be used. Combinations of several types of signals may be used insome embodiments. In some embodiments, control signal generationcircuitry 906 may cause release of material from material releasestructure in response to passage of a certain amount of time, asmonitored, for example, by a timekeeping device. In some embodiments,material release structure 908 may include a pressurized reservoir ofmaterial. In still other embodiments, the material (or materials) to bereleased may be generated within the material release structure. Inother embodiments, the material(s) may diffuse away from the releasestructure along a concentration gradient.

FIG. 17 illustrates, in cross sectional view, a structural element 950of a lumen-traveling device positioned in a lumen-containing structure952. A reservoir 954 contains stored deliverable material. Barrier 956is a controllable barrier that control the release of the storeddeliverable material into central opening 958, and thus into a fluidthat fills and/or flows through lumen-containing structure 952.

FIG. 18 illustrates an embodiment similar to that depicted in FIG. 20,including a structural element 1000 of a lumen-traveling devicepositioned in a lumen-containing structure 1002. A reservoir 1004contains stored deliverable material. Barrier 1006 is a controllablebarrier that controls the release of the stored deliverable material. Inthe embodiment of FIG. 18, activation of barrier 1006 causes release ofthe stored deliverable material toward the lumen wall oflumen-containing structure 1002, rather than into central opening 1008.

FIGS. 19A, 19B, 20A, 20B, 22A and 22B, illustrate several alternativeembodiments of material release structures that include controllablebarriers. In FIGS. 19A and 19B, release structure 1150 includesreservoir 1152 containing stored deliverable material 1154. As shown inFIG. 19A, while rupturable barrier 1156 is intact, stored deliverablematerial 1154 is contained within reservoir 1152. As shown in FIG. 19B,when rupturable barrier 1156 has been ruptured (as indicated byreference number 1156′), deliverable material 1154 may be released fromreservoir 1152. Rupturable barrier 1156 may be ruptured by an increaseof pressure in reservoir 1152 caused by heating, for example, which maybe controlled by response initiation circuitry. In another alternativeshown in FIGS. 20A and 20B, release structure 1200 includes reservoir1202 containing stored deliverable material 1204. As shown in FIG. 20A,while degradable barrier 1206 is intact, stored deliverable material1204 is contained within reservoir 1202. As shown in FIG. 20B,degradation of degradable barrier 1206 to degraded form 1206′ causesstored deliverable material 1204 to be released from reservoir 1204.FIGS. 21A and 21B depict release structure 1250 including reservoir 1252containing stored deliverable material 1254. FIG. 21A shows barrier1256, which has a controllable permeability, in a first, impermeablestate, while FIG. 21B shows barrier 1256 in a second, permeable state(indicated by reference number 1256′). Stored deliverable material 1254passes through barrier 1256′, when it is in its permeable state, and isreleased. Rupturable barriers as described above may be formed from avariety of materials, including, but not limited to, metals, polymers,crystalline materials, glasses, ceramics, semiconductors, etc. Releaseof materials through rupture or degradation of a barrier is alsodescribed in U.S. Pat. No. 6,773,429, and U.S. Patent Application2004/0260391, which are incorporated herein by reference. Semipermablebarriers having variable permeability are described, for example, inU.S. Pat. No. 6,669,683, which is incorporated herein by reference.Those of skill in the art will appreciate that barriers can be formedand operated reversibly through multiple release cycles, in addition tothe single-release functionality available from a rupturable barrier.

FIG. 22 depicts another embodiment of a structural element of alumen-traveling device 1300 in a lumen containing structure 1302.Lumen-traveling device 1300 includes stored deliverable material 1304dispersed in a carrier material 1306. Stored deliverable material 1304may be released from carrier material 1306 by release mechanism 1308upon activation of release mechanism 1308. Released deliverable material1304 may be released into central opening 1310 of lumen-traveling device1300 and/or into the area around the lumen-traveling device.

FIGS. 23A and 23B depict in greater detail the release of storeddeliverable material from the carrier material. In FIG. 23A, deliverablematerial 1304 is stored in carrier material 1306. Carrier material 1306may be, for example, a polymeric material such as a hydrogel, anddeliverable material is dispersed or dissolved within carrier material1306. Release mechanism 1308 may be a heating element, for example aresistive element connected directly to response initiation circuitry,or an electrically or magnetically responsive material that may becaused to move, vibrate or heat, by an externally appliedelectromagnetic field, which in turn causes release of deliverablematerial 1304 from carrier material 1306, as shown in FIG. 23B. See, forexample, U.S. Pat. Nos. 5,019,372 and 5,830,207, which are incorporatedherein by reference. In some embodiments, an electrically ormagnetically active component may be heatable by an electromagneticcontrol signal, and heating of the electrically or magnetically activecomponent may cause the polymer to undergo a change in configuration. Anexample of a magnetically responsive polymer is described, for example,in Neto, et al, “Optical, Magnetic and Dielectric Properties ofNon-Liquid Crystalline Elastomers Doped with Magnetic Colloids”;Brazilian Journal of Physics; bearing a date of March 2005; pp. 184-189;Volume 35, Number 1, which is incorporated herein by reference. Otherexemplary materials and structures are described in Agarwal et al.,“Magnetically-driven temperature-controlled microfluidic actuators”; pp.1-5; located at:http://www.unl.im.dendai.ac.jp/INSS2004/INSS2004_papers/OralPresentations/C2.pdfor in U.S. Pat. No. 6,607,553, both of which are incorporated herein byreference. In connection with the release of materials and/or detectionof a local condition, in some embodiments the permeability of the lumenwall to the released material may be increased by the use of retractableprotrusions that penetrate the lumen wall, as described in U.S. Pat. No.6,991,617; by hollow microneedles capable of penetrating the lumen wall,as described in U.S. Pat. No. 6,743,211; by introduction of a magneticor electromagnetic field (Physical and Chemical Permeation Enhancers inTransdermal Delivery of Terbutaline Sulphate, AAPS Pharm Sci Tech, 2001;2 (1) 1-5; http://www.aapspharmscitech.org/view.asp?art=pt0201_tnl); bya chemical permeability enhancer as described in U.S. Pat. No.6,673,363, which may be released from the lumen-traveling deliverydevice along with the material or from a separate reservoir or othersource or which may be incorporated within a component of the device forexample as a coating; or by an electrical permeability enhancer, such asa voltage source for producing electroporation and/or iontophoresis, asin U.S. Pat. Nos. 6,022,316, 6,219,577, 6,512,950; or by sonophoresis orphonophoresis, perhaps using techniques based on those in U.S. Pat. No.6,322,532; all of which patents are incorporated herein by reference intheir entirety. Chemical permeation enhancers may include, for example,isopropyl myristate, bile salts, surfactants, fatty acids andderivatives, chelators, cyclodextrins, or chitosan. Other technologiesthat might be useful for enhancing permeability may includeiontophoresis, microdialysis, ultrafiltration, electromagnetic, osmotic,electroosmosis, sonophoresis, suction, electroporation, thermalporation, microporation, microfine cannulas, skin permeabilization, or alaser.

The active portion may include a device release structure operativelycoupled to the response initiation circuitry and configured to release adevice in response to receipt of the response initiation signal. Forexample, FIG. 24 illustrates a lumen-traveling device 1350 includingdevice release structure 1352 (which in this example is a grasper typestructure) holding a device 1354 that is to be released into a bodylumen. Response initiation circuitry 1356 may receive a sense signalfrom sensor 1358, and generate a response initiation signal to causedevice release structure 1352 to release device 1354. Device 1354 may beany type of device small enough to be carried by a lumen-travelingdevice. For example, device 1354 might be a sensor with a transmitter, adevice that releases a drug or other compound, or an electromagneticstimulation device. The device configuration illustrated in FIG. 24 isintended as an example only, and the device released by a device releasestructure of a lumen-traveling device may have various configurations.It will be appreciated that the device release structure may be designedto be compatible with a particular type of device, or may be suitablefor use with a number of types of devices.

As illustrated in FIGS. 25A and 25B, the active portion of alumen-traveling device 1400 may include a delivery structure 1402operatively coupled to the response initiation circuitry 1404 andconfigured to deliver a material or structure 1408 to a receiving devicein 1410 response to receipt of the response initiation signal. In FIG.25A, lumen-traveling device 1400 includes delivery structure 1402, whichis capable of attaching to connector 1406 on structure 1408, thuspermitting structure 1408 to be carried by lumen-traveling device 1400.In use, lumen-traveling device 1400 may carry structure 1408 toreceiving device 1410. A response initiation signal may be generated byresponse initiation circuitry 1404 when lumen-traveling device 1400 isclose to receiving device 1410. Receiving device 1410 may include areceiving structure 1413 made up of recess 1412 and receiving arms 1414mounted on pivots 1416. Receiving device 1410 may be a non-mobile deviceor structure that has been implanted or placed in the lumen, or, in someembodiments, receiving device 1410 may be a second lumen-travelingdevice. The second lumen-traveling device may include various featuresas described previously; the active portion may include a receivingstructure (e.g., receiving structure 1413 in FIGS. 25A and 25B)operatively coupled to the response initiation circuitry and configuredto receive a material or structure (e.g., structure 1408) from adelivering device 1400 in response to receipt of the response initiationsignal. As structure 1408 is pushed into receiving recess 1412,receiving arms 1414 may be caused to move on pivots 1416 to allowstructure 1408 to slide into recess 1412, where it may be retained byprojections 1418, as illustrated in FIG. 25B.

The active portion may include a collecting structure operativelycoupled to the response initiation circuitry and configured to collect astructure (including, but not limited to, a man-made structure) from thebody lumen in response to receipt of the response initiation signal. Thecollecting structure may be comparable to a device release structure asdepicted previously, and may collect a structure from the body lumen byattaching to a connector such as connector 1406. In related embodiments,the collecting structure may grasp the body of a device-to-be-collected,generally as depicted in FIG. 24. In other embodiments, a collectingstructure may be large enough to receive the structure to be collectedwithin the body of the lumen-traveling device.

The active portion of a lumen-traveling device may include an attachmentstructure operatively coupled to the response initiation circuitry andconfigured to attach to a structure (particularly a man-made structure)present in the body lumen in response to receipt of the responseinitiation signal. The attachment structure may be a grasper shown inFIG. 24 or the device release structure shown in FIGS. 25A and 25B.Other attachment mechanisms may include various other mechanicalmechanisms, or be based on magnetic attraction, electrostatic forces,chemical bonding, surface interactions, etc. Microscale structures forgripping or grasping are described in U.S. Pat. No. 6,398,280, and“Zyvex NanoEffector Microgrippers”; Nanotechnology at Zyvex; printed onDec. 7, 2006; pp. 1-2; located athttp://www.zyvex.com/Products/Grippers_Features.html and “ZyvexNanoEffector Microgrippers”; Zyvex.com; bearing a date of 2006; pp. 1-2;Zyvex Corporation, all of which are incorporated herein by reference.

The active portion may include one or more tools, especially surgicaltools, e.g., tools for cutting, as depicted in FIGS. 26A and 26B,scraping, as depicted in FIG. 27, suturing, or cauterizing. In FIG. 26A,a lumen-traveling device 1450 includes a cutting tool 1452 mounted onshaft 1454, which may be retracted into channel 1456, driven bytranslation motor 1458. In the embodiment depicted in FIG. 26A,lumen-traveling device 1450 includes main lumen 1460. A cross-section oflumen-traveling device 1450 taken at section line B-B, showing shaft1454, channel 1456, and main lumen 1460 is illustrated in FIG. 26B.Channel 1456 and main lumen 1460 pass through core portion 1462 oflumen-traveling device 1450.

FIG. 27 depicts a lumen-traveling device 1500, generally similar tolumen-traveling device 1450 in FIGS. 26A and 26B, but including ascraping tool 1502. Scraping tool 1502 is mounted on shaft 1504 whichmay retract in channel 1506. Shaft 1504 may also rotate in channel 1506,both during use of scraping tool 1502, as illustrated with thedouble-headed arrow, and also to permit the scraping tool 1502 to beretracted into main lumen 1508 of the lumen-traveling device, to theposition shown in dashed lines. An example of a scraping tool ispresented in JP 2005-74229, which is incorporated herein by reference.

Various examples of suturing tools are disclosed and described in U.S.Pat. Nos. 7,131,979 and 5,964,773, both of which are incorporated hereinby reference. A cauterizing tool may be a specialized form of a heatingelement, as depicted in FIG. 7A, or electromagnetic radiation source asdepicted in FIG. 7C. Tools may be micro-scale tools formed by MEMSmanufacturing techniques, e.g., as described in U.S. Pat. No. 5,728,089,which is incorporated herein by reference. It will be appreciated thatvarious other active portions disclosed herein may also have surgicalutility: for example, active portions for performing sample collection,material release, heating, cooling, etc. may all have surgicalapplications.

FIG. 28 depicts a system 1600 including a lumen-traveling device 1602located in a body lumen 1604 (here, a portion of the circulatory system)and a remote portion 1606, which in this example is located outside bodysurface 1608. In some embodiments, a remote portion may be locatedinside the body at a distance from the lumen-traveling device. Theactive portion of a lumen-traveling device 1602 may include atransmitter 1610 operatively coupled to the response initiationcircuitry and configured to transmit a detection signal 1612 to a remotelocation (e.g., remote portion 1606) in response to receipt of theresponse initiation signal. The detection signal may be used to inform amedical caregiver about a condition of the subject so that suitabletreatment may be provided by the caregiver, or the detection signal maycontain information usable by an automated system to control operationof the lumen-traveling device.

Various types of propelling mechanisms may be used to move thelumen-traveling device through the body lumen. Examples are provided inU.S. Pat. Nos. 5,337,732; 5,386,741; 5,662,587; and 6,709,388; andKASSIM, IRWAN; PHEE, LOUIS; NG, WAN S.; GONG, FENG; DARIO, PAOLO; MOSSE,CHARLES A. (“Locomotion Techniques for Robotic Colonoscopy”; IEEEENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE; bearing dates of May/June2006 and 2006; pp. 49-56; IEEE); CHRISTENSEN, BILL (“Musclebot:Microrobot with a Heart”; Technovelgy.com; pp. 1-2; bearing a date ofFeb. 27, 2004; located athttp://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=46;printed on Sep. 12, 2006); ANANTHASWAMY, ANIL (“First robot moved bymuscle power”; bearing a date of Feb. 27, 2004; pp. 1-3; New Scientist;located at http://www.newscientist.com/article.ns?id=dn4714; printed onSep. 12, 2006); and FREITAS JR., ROBERT A. (“8.2.1.2 ArteriovenousMicrocirculation”; “9.4.3.5 Legged Ambulation”; “9.4.3.6 Tank-TreadRolling”; “9.4.3.7 Amoeboid Locomotion”; “9.4.3.8 Inchworm Locomotion”;“Nanomedicine Volume I: Basic Capabilities”; bearing a date of 1999; pp.211-214, pp. 316-318; Landes Bioscience; Georgetown, Tex., USA); all ofwhich are incorporated herein by reference in their entirety. Thepropelling mechanism of the lumen-traveling device may include one ormore cilium-like or flagellum-like structures, for example, as describedin U.S. Patent Application 2004/0008853; MATHIEU, J-B.; MARTEL, S.;YAHIA, L'H.; SOULEZ, G.; BEAUDOIN, G. (“MRI Systems as a Mean ofPropulsion for a Microdevice in Blood Vessels”; bearing a date of 2003;pp. 3419-3422; IEEE); LU, ZHAO; MARTEL, SYLVAIN (“PreliminaryInvestigation of Bio-carriers Using Magnetotactic Bacteria”; Proceedingsof the 28th IEEE EMBS Annual International Conference; bearing dates ofAug. 30, 2006-Sep. 3, 2006 and 2006; pp. 3415-3418; IEEE), and MARTEL,SYLVAIN (“Towards MRI-Controlled Ferromagnetic and MC-1 MagnetotacticBacterial Carriers for Targeted Therapies in Arteriolocapillar NetworksStimulated by Tumoral Angiogenesis”; Proceedings of the 28th IEEE EMBSAnnual International Conference; bearing dates of Aug. 30, 2006-Sep. 3,2006 and 2006; pp. 3399-3402; IEEE), all of which are incorporatedherein by reference. The propelling mechanism may include rollers orwheel-like structures, as shown in U.S. Pat. No. 7,042,184 and U.S.Patent Application 2006/0119304, both of which are incorporated hereinby reference; screw-like structures, as disclosed in IKEUCHI, K.;YOSHINAKA, K.; HASHIMOTO, S.; TOMITA, N. (“Locomotion of Medical MicroRobot with Spiral Ribs Using Mucus”; Seventh International Symposium onMicro Machine and Human Science; bearing a date of 1996; pp. 217-222;IEEE), which is incorporated herein by reference; appendages capable ofwalking motion, as described, for example, in U.S. Pat. No. 5,574,347;CHRISTENSEN, BILL (“Musclebot: Microrobot with a Heart”;Technovelgy.com; pp. 1-2; bearing a date of Feb. 27, 2004; located athttp://www.technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=46;printed on Sep. 12, 2006) and MARTEL, SYLVAIN (“Fundamentals ofhigh-speed piezo-actuated three-legged motion for miniature robotsdesigned for nanometer-scale operations”; pp. 1-8), incorporated hereinby reference, and others. Appendage-like structures may intermittentlyengage the lumen wall and push the structural element with respect tothe lumen wall with a walking-type motion, or may push against fluidwithin the lumen in a paddling or swimming motion. In some embodiments,the propelling mechanism may drive rotational movement of alumen-wall-engaging structure with respect to the structural element,e.g., as in turning of a wheel or a screw element to propel thestructural element through a lumen. Propelling mechanisms may includemechanical or micromechanical structures driven by at least one motor,micromotor, or molecular motor, or by expansion or change inconfiguration of a shape change polymer or metal. A molecular motor maybe a biomolecular motor that runs on a biological chemical such as ATP,kinesin, RNA polymerase, myosin dynein, adenosinetriphosphatesynthetase, rotaxanes, or a viral protein.

FIG. 1 depicts an example of a lumen-traveling device that includes apropelling mechanism which drives rotational movement of alumen-wall-engaging structure. Lumen-traveling device 10 may include astructural element 12 configured to fit within at least a portion of abody lumen 14. The structural element 12 may include alumen-wall-engaging portion 16. Lumen-traveling device 10 may alsoinclude a propelling mechanism 20 capable of producing movement of thestructural element 12 through a body lumen 14 in which the structuralelement is deployed. Here, propelling mechanism 20 includes two rotatingwheels, the outer rims of which form lumen-wall-engaging portions 16.

In several alternative approaches, two (or more) lumen-wall-engagingportions may engage the lumen walls intermittently. FIGS. 29A-29 Edepict (in cross-section) an embodiment of a lumen-traveling device 1650which includes a motion-arresting portion including a firstlumen-wall-engaging structure 1652 on first portion 1654 of thelumen-traveling device, capable of at least intermittently engaging aninner surface 1658 of body lumen in which the lumen-traveling device1650 is deployed. The device may also include at least one secondlumen-wall-engaging structure 1660 on second portion 1662 of thelumen-traveling device, wherein the propelling mechanism produceslengthening and shortening of the distance, between the firstlumen-wall-engaging structure 1652 and the second lumen-wall-engagingstructure 1660 in coordination with alternate engagement of the firstlumen-wall-engaging structure 1652 and the second lumen-wall-engagingstructure 1660 with the inner surface 1658 of the body lumen in whichthe lumen-traveling device is deployed. In the present example, thelengthening and shortening of the distance between the first and secondlumen-wall-engaging structures may take place in region 1664, but inother embodiments, the distance between the first and secondlumen-wall-engaging structures may change due to change in position ofthe lumen-wall-engaging structures, e.g., in limbs that move relative toeach other to produce walking-type motion. Portions of thelumen-traveling device (e.g. end portion 1656) may not change in length,in order to provide a stable location for mounting of control circuitry(not shown). The alternate engagement and disengagement of the lumenwall by the first and second lumen-wall-engaging structures may produceinchworm-type propulsion of the device through the body lumen.Lumen-traveling device 1650 includes a propelling mechanism capable ofproducing relative extension and retraction of the at least twolumen-wall-engaging structures (1652 and 1660) with respect to eachother in combination with alternate engagement and disengagement of thebody lumen wall to produce inch-worm-like movement of thelumen-traveling stimulation device with respect to the body lumen wall.The embodiment of the lumen-traveling device depicted in FIGS. 29A-29Ehas a tubular structure with a central lumen 1668, to permit movement offluid through the device. FIG. 29A depicts lumen-traveling device inwhich lumen-wall-engaging structures 1652 and 1660 are extended toengage with inner surface 1658. In FIG. 29B, second lumen-wall-engagingstructure 1660 has been retracted, and region 1664 shortened to causemovement of second portion 1662 of lumen-traveling device 1650 in thedirection indicated by the arrow, to attain the configuration shown inFIG. 29C. Second lumen-wall-engaging structure 1660 is then extended toengage inner surface 1658, and first lumen-wall-engaging structure 1652is retracted, to attain the configuration shown in FIG. 29D. Then, asindicated in the arrow in FIG. 29D, region 1664 is extend to move firstportion 1654 of lumen-traveling device 1650 in the direction indicatedby the arrow in FIG. 29D. At the end of the movement cycle,lumen-traveling device 1650 has attained the configuration shown in FIG.29E. First lumen-wall-engaging structure 1652 may then be extended toengage inner surface 1658, as depicted in FIG. 29A. It will beappreciated that by repeating the motion cycle illustrated in FIGS.29A-29E, movement of the lumen-traveling device through the lumen may beaccomplished. Various types of lumen-wall-engaging structures may beused in devices that produce inchworm-type motion, and in addition tolumen-wall-engaging structures that expand or extend, structures thatengage the lumen wall through other mechanisms (for example, withsuction mechanisms, adhesives, claws or hooks) may be used.Lumen-traveling devices that utilize an inchworm-type propulsionmechanism with suction mechanisms for engaging the surface of the heartare disclosed in PATRONIK, N. A.; OTA, T.; ZENATI, M. A.; RIVIERE, C. N.(“Improved Traction for a Mobile Robot Traveling on the Heart”;Proceedings of the 28^(th) IEEE EMBS Annual International Conference;bearing dates of Aug. 30, 2006-Sep. 3, 2006 and 2006; pp. 339-342;IEEE); DARIO, P.; CARROZZA, M. C.; LENCIONI, L.; MAGNANI, B.;D'ATTANASIO, S. (“A Micro Robotic System for Colonoscopy”; Proceedingsof the 1997 IEEE International Conference on Robotics and Automation;bearing dates of April 1997 and 1997; pp. 1567-1572; IEEE) andDONGXIANG, CHI; GUOZHENG, YAN (“An earthworm based miniature robot forintestinal inspection”; Proceedings of SPIE; bearing dates of Nov. 7,2001-Nov. 9, 2001; pp. 396-400; Volume 4601; SPIE); all of which areincorporated herein by reference in their entirety.

Radially and longitudinally expanding or extending structures may bemechanical or micromechanical structures, expandable materials,inflatable structures, or shape-changing materials or structures. Whilereference is made to expandable and inflatable materials and structureshere, and throughout the specification, it will be appreciated thatstructures that are specified as being expandable and inflatable mayalso be contractible or deflatable, and thus capable of reversiblechange in dimension. Reversible changes of dimension may be used ingenerating cyclical motions for propelling a lumen-traveling device. Insome embodiments, expansion/contraction may force fluid out of thedevice to generate jet or vortex propulsion. Nevertheless, it iscontemplated that, in some applications, materials and structures thatchange dimension in one direction (only expansion or only contraction)may be used.

FIGS. 30A and 30B depict the use of shape-changing structure forengagement of a lumen wall and extension of a body structure of alumen-traveling device. In FIG. 30A, lumen-traveling device 1700includes shape-changing arc 1702, which may have a curved configuration,as shown in FIG. 30A, or an extended configuration as shown in FIG. 30B.Such a change in configuration may be produced by heating of abimetallic strip, or by the use of a shape memory material having atleast two configurations, and may be used to provide lengthening andshortening of lumen-traveling device 1700. Lumen-traveling device mayinclude a first lumen-wall-engaging structure 1704 and secondlumen-wall-engaging structure 1706. First lumen-wall-engaging structure1704 is formed from a strip of material formed into first and secondloops 1708 and 1710, respectively. In FIG. 30A, first loop 1708 issmall, and second loop 1710 is large, so that it engages lumen walls1720. Second lumen-wall-engaging structure 1706 is formed of first loop1714 and second loop 1716, which in FIG. 30A are of medium size, so thatneither engages lumen walls 1720. First lumen-wall-engaging structure1704 is connected to lumen-traveling device 1700 at mounting point 1712,which includes a translational mechanism for moving first loop 1708 withrespect to second loop 1712 to change the size of the two loops.Similarly, second lumen-wall-engaging structure 1706 is connected tolumen-traveling device 1700 at mounting point 1718, which includes atranslational mechanism for moving first loop 1714 with respect tosecond loop 1716 to change the size of the two loops. In FIG. 30B, arc1702 is extended, so that second lumen-wall-engaging structure 1706 hasmoved from point B (in FIG. 30A) to point C (in FIG. 30B). First loop1714 of second lumen-wall-engaging structure 1706 has been reduced insize by a translational mechanism at mounting point 1718, while secondloop 1716 has been increased in size to engage lumen walls 1720.Inchworm motion similar to that depicted in FIGS. 29A-29E can thus beproduced by an embodiment of lumen-traveling device as depicted in FIGS.30A and 30 B.

FIG. 31 depicts a further embodiment of a lumen-traveling device adaptedto travel through the body lumen with a propelling mechanism thatproduces walking-type motion. The lumen-traveling device may include twoor more lumen-wall-engaging structures on a portion of thelumen-traveling device capable of at least intermittently engaging aninner surface of a body lumen in which the lumen-traveling device isdeployed, wherein the propelling mechanism drives walking movement ofthe two or more lumen-wall-engaging structures with respect to innersurface of the body lumen. Lengthening and shortening of the distancebetween the lumen-wall-engaging structures is produced by change in legconfiguration rather than by lengthening or shortening of the mainstructure (e.g. body structure) of the lumen-traveling device.Lumen-traveling device 1750 includes a structural element 1751 sized tofit within a body lumen; at least two lumen wall-engaging structuresoperable to alternately engage and disengage a wall of the body lumen(in FIG. 31, 6 lumen-wall-engaging structures 1752, 1754, 1756, 1758,1760, and 1762 are shown); a propelling mechanism capable of producingrelative extension and retraction of the at least twolumen-wall-engaging structures with respect to each other in combinationwith alternate engagement and disengagement of the body lumen wall 1764to produce movement of the lumen-traveling stimulation device withrespect to the body lumen wall. Lumen-traveling device 1750 may alsoinclude motion control circuitry carried at least in part by thelumen-traveling device and configured to control the propellingmechanism to control movement of the lumen-traveling device through thebody lumen; a sensor capable of detecting a condition of interest in thebody lumen; and an active portion carried by the structural element andconfigured to perform an action in response to detection of thecondition of interest by the sensor, not shown in FIG. 31 but operatingas described elsewhere herein. The at least two lumen-wall-engagingstructures may include at least two appendages configured for walkingmotion. In the embodiment shown in FIG. 31, legs 1752 and 1754 extendand retract with respect to each other, for example, so that as one legswings forward, the other swings back. Larger or smaller numbers oflegs, distributed in various patterns about the structural element, maybe used to propel the lumen-traveling device through the body lumen, andthe embodiment depicted in FIG. 31 represents one possible example.

Leg structures for lumen-traveling devices may be formed of variousmaterials and structures, including nanotubes and nanotube bundles,carbon fibers and carbon fiber bundles, silicon, metal, polymers, andother materials as described herein. Legs may be moved to producewalking motion may be actuated by various mechanisms. In someembodiments the legs formed from shape-changing material may be movedthrough change in configuration of the leg structure itself, while inother embodiments the leg may have a substantially rigid or fixedconfiguration that may be moved by separate actuation mechanism.Shape-changing materials that may be used in leg structures or actuatorsmay be of various types, for example, stacked piezoelectric elements,electroactive polymers, heat sensitive polymers, magnetic fieldresponsive polymers, and ferromagnetic materials, as described elsewhereherein. In some embodiments, motors and actuators may be used to driveleg motion, as known to those of skill in the art.

In another embodiment of a propelling mechanism, as depicted in FIGS. 32and 32, multiple lumen-wall-engaging structures, operating in sequenceto alternately engage and disengage the lumen wall, may be used toproduce “peristaltic” motion of the lumen-traveling device. Examples ofdevices that produce this type of motion are described in U.S. Pat. No.6,764,441; U.S. Patent Application 2006/0004395; MANGAN, ELIZABETH V.;KINGSLEY, DAN A.; QUINN, ROGER D.; CHIEL, HILLEL J.; “Development of aPeristaltic Endoscope”; IEEE International Conference on Robotics &Automation 2002; pp. 1-6; located athttp://biorobots.cwru.edu/publications/ICRA02_Mangan_Endoscope.pdf; andMEIER, P.; OBERTHÜR, S.; LANG, M.; “Development of a compliant devicefor minimally invasive surgery”; Proceedings of the 28^(th) IEEE EMBSAnnual International Conference; bearing dates of Aug. 30, 2006-Sep. 3,2006 and 2006; pp. 331-334; IEEE; all of which are incorporated hereinby reference.

In FIGS. 32A and 32B, lumen-traveling device 1800 includes structuralelement 1802, which may be formed of a resilient material. Structuralelement 1802 may be a substantially tubular structure with a centrallumen 1816, for example. A plurality of expanding or extendingstructures 1804, 1806, 1808, 1810, 1812, 1814, and 1818 may bepositioned along the length of structural element 1802. Expanding orextending structures may expand in a lengthwise direction as well asexpanding in a radially outward direction. For example, in FIG. 32A,expanding or extending structures 1804 and 1810 are shown in theirexpanded configurations, in which they are both wider and longer than intheir contracted configurations as shown in FIG. 32B. Conversely,expanding or extending structures 1806, 1808, 1812, and 1814 are shownin the contracted configurations in FIG. 32A, and in their expandedconfigurations in FIG. 32B. By expanding and contracting the expandingor extending structures in sequence, as depicted in FIGS. 32A and 32B,movement of the lumen-traveling device through the body lumen may beaccomplished.

In some embodiments, a propelling mechanism may be configured to drivemovement of the lumen-traveling device along a wire, catheter, cannula,or tube within the body lumen. For example, as shown in FIG. 33,lumen-traveling device 1850 moves along elongated structure 1852 (whichmay be, for example, a wire, catheter, cannula, tube or other structure)located within body lumen 1854, surrounded by lumen walls 1856.Lumen-traveling device 1850 includes body structure 1858, retainer 1860,and propelling mechanism 1862. In the example depicted in FIG. 33,retainer 1860 is a hook-like structure that holds lumen-traveling device1850 against elongated structure 1852 while allowing it to move alongelongated structure 1852, while propelling mechanism 1862 causeslumen-traveling device 1850 to move along elongated structure 1852. Inthe embodiment of FIG. 33, propelling mechanism 1862 is a rotating wheelthat moves lumen-traveling device 1850 along elongated structure 1852,but in other embodiment, other propelling mechanisms may be used to movea lumen-traveling device along an elongated structure.

Finally, as noted elsewhere herein, in some embodiments, thelumen-traveling device may be propelled through the body lumen by one ormore paddles, propellers, vortex generators, jets, flagellum-likestructures, or the like, which push against fluid contained within thelumen rather than engaging the wall of the body lumen, e.g. as describedin U.S. Pat. No. 6,240,312 or in BEHKAM, BAHAREH; SITTI, METIN; “TOWARDSHYBRID SWIMMING MICROROBOTS: BACTERIA ASSISTED PROPULSION OF POLYSTYRENEBEADS”; Proceedings of the 28^(th) IEEE EMBS Annual InternationalConference; bearing dates of Aug. 30, 2006-Sep. 3, 2006 and 2006; pp.2421-2424; IEEE; CHRISTENSEN, BILL; “Propulsion System for ‘FantasticVoyage’ Robot”, bearing a date of Nov. 10, 2006, printed on Jan. 4,2007, located athttp://technovelgy.com/ct/Science-Fiction-News.asp?NewsNum=811; or“Researchers: Squid-Inspired Vortex Generators Could Mean BetterPropulsion for Unmanned Underwater Vehicles”; UnderwaterTimes.com; Dec.12, 2006; pp. 1-2; printed on Jan. 4, 2007; located athttp://www.underwatertimes.com/print.php?article_id=51030782641; orMOHSENI, KAMRAN; “Biomimemetic & Bio-Inspired Aerial and UnderwaterVehicles”; bearing a date of Sep. 23, 2006; pp. 1-100 printed on Jan. 4,2007, located athttp://enstrophy.colorado.edu/˜mohseni/MicroVehicles1.html#UUV1#UUV1 allof which are incorporated herein by reference.

The direction of movement produced by the various propelling mechanismsdescribed herein may be reversed by simply reversing the operation ofthe propelling mechanisms.

In various embodiments as described herein, a lumen-traveling device mayinclude a power source configured to provide power to at least one ofthe propelling mechanism, the motion control circuitry, the sensor, theresponse initiation circuitry, or the active portion. The power sourcemay be a battery or microbattery, a fuel cell or biofuel cell, or anuclear battery. One or more power sources of the same or differenttypes may be included in the lumen-traveling device, without limitation.Batteries may be located on the lumen-traveling device, possibly amicrobattery like those available from Quallion LLC(http://www.quallion.com) or designed as a film (U.S. Pat. Nos.5,338,625 and 5,705,293), which are incorporated herein by reference.Alternatively, the power source could be one or more fuel cell such asan enzymatic, microbial, or photosynthetic fuel cell or other biofuelcell (US2003/0152823A1; WO03/106966A2; or Chen T et al. J. Am. Chem.Soc. 2001, 123, 8630-8631, A Miniature Biofuel Cell, all of which areincorporated herein by reference), and could be of any size, includingthe micro- or nano-scale. In some embodiments, the power source may be anuclear battery. The power source may be an energy-scavenging devicesuch as a pressure-rectifying mechanism that utilizes pulsatile changesin blood pressure, for example, or an acceleration-rectifying mechanismas used in self-winding watches, or other types of flow-rectifyingmechanism capable of deriving energy from other flow parameters. In someembodiments, the power source may be an electrical power source locatedremote from the structural element and connected to the structuralelement by a wire, or an optical power source located remote from thestructural element and connected to the structural element by afiber-optic line or cable. In some embodiments, the power source may bea power receiver capable of receiving power from an external source, forexample, an acoustic source or electromagnetic source (e.g., infraredenergy, or inductively coupled, as described in U.S. Pat. No. 6,170,485or U.S. Patent Application No. 2005/0228259, which are incorporatedherein by reference). In some embodiments, the power source may includean electrical power source located remote from the lumen-travelingdevice and connected to the lumen-traveling device by a wire, or anoptical power source located remote from the lumen-traveling device andconnected to the lumen-traveling device by an optical fiber.

In some embodiments, the lumen-traveling device may include a powertransmitter capable of transmitting power from the lumen-travelingdevice to a secondary location. The power transmitter may be capable oftransmitting at least one of acoustic power, electrical power, oroptical power. The secondary location may be, for example, anotherdevice within the body, either in a body lumen or elsewhere, thatincludes a power receiver and structures for using, storing and/orre-transmitting the received power.

FIG. 34 is a block diagram depicting a further embodiment of alumen-traveling device 1900, which includes a motion-arresting portion1902; a fluid-contacting portion 1904 configured to contact fluid withinthe body lumen and to at least intermittently permit flow of fluidthrough the body lumen; a propelling mechanism 1906 capable of producingmovement of the lumen-traveling device through a body lumen in which thelumen-traveling device is deployed; motion control circuitry 1908carried at least in part by said lumen-traveling device and configuredto control propelling mechanism 1906 to control movement of thelumen-traveling device through the body lumen; a sensor 1910 capable ofdetecting a condition of interest in the body lumen and generating asense signal indicating detection of the condition of interest; responseinitiation circuitry 1912 operatively connected to sensor 1910 andconfigured to generate a response initiation signal upon receipt of thesense signal indicating detection of a condition of interest in the bodylumen; and an active portion 1914 operatively connected to responseinitiation circuitry 1912 and capable of producing a response uponreceipt of the response initiation signal. Motion control circuitry 1908and response initiation circuitry 1912 make up part of control circuitry1907, which may also include other components not specifically describedherein. The embodiment of FIG. 34 also includes a steering mechanism1916 capable of modifying the direction of movement of thelumen-traveling device; wherein the motion control circuitry 1908 may beconfigured to control the steering mechanism 1916 to control movement ofthe lumen-traveling device through the body lumen. The embodiment ofFIG. 34 may include power source 1918 configured to provide power to atleast one of propelling mechanism 1906, steering mechanism 1916, motioncontrol circuitry 1908, sensor 1910, response initiation circuitry 1912or active portion 1914. Components of the embodiment of FIG. 34 may begenerally as described elsewhere herein. Steering mechanism 1916 may beany of various structures, depending on the type of propelling mechanismused. If the propelling mechanism is a paddle or propeller that causesthe lumen-traveling device to move in the fluid in the lumen, thesteering mechanism may be a rudder. If the propelling mechanism includesmultiple wheels or limb-like structures, they may be activateddifferentially on different sides of the lumen-traveling device to steerit in one direction or another. In embodiments in which thelumen-traveling device contacts the lumen walls on all sides of thedevice, the steering mechanism may be used only in the cases that thelumen-traveling device encounters a branch point in the lumen, and oncethe front portion of the device (defined by the direction of travel) issteered to cause the device to enter a selected branch, the back portionof the device will follow without the need for additional steering.

Various embodiments of the lumen-traveling device may include a markeror tag. The marker or tag may be an imaging marker or tag detectable bya remote imaging system to indicate the position of the lumen-travelingdevice within the body of a subject (for example, a radio-opaque markerfor x-ray imaging). Alternatively, the marker or tag may be detectableby a sensing device or structure within the body of the subject.

In some embodiments, as depicted in FIG. 35, at least a portion of thecircuitry that controls the operation of the lumen-traveling device 1950may be located remote from the lumen-traveling device in remote portion1972, outside the body of the subject as shown in FIG. 28, or at alocation within the body of the subject at a distance from thelumen-traveling device. In the embodiment of FIG. 35, lumen-travelingdevice 1950 includes a motion-arresting portion 1952; a fluid-contactingportion 1954 configured to contact fluid within the body lumen and to atleast intermittently permit flow of fluid through the body lumen; apropelling mechanism 1956 capable of producing movement of thelumen-traveling device through a body lumen in which the lumen-travelingdevice is deployed; motion control circuitry 1958 carried at least inpart by said lumen-traveling device and configured to control propellingmechanism 1956 to control movement of the lumen-traveling device throughthe body lumen; a sensor 1960 capable of detecting a condition ofinterest in the body lumen and generating a sense signal indicatingdetection of the condition of interest; response initiation circuitry1962 operatively connected to sensor 1960 and configured to generate aresponse initiation signal upon receipt of the sense signal indicatingdetection of a condition of interest in the body lumen; and an activeportion 1964 operatively connected to response initiation circuitry 1962and capable of producing a response upon receipt of the responseinitiation signal. The embodiment of FIG. 35 includes a steeringmechanism 1966 capable of modifying the direction of movement of thelumen-traveling device; wherein the motion control circuitry 1958 may beconfigured to control the steering mechanism 1966 to control movement ofthe lumen-traveling device through the body lumen. At least a portion ofthe control circuitry for lumen-traveling device 1950, remote circuitry1974, may be located remote from lumen-traveling device 1950 in remoteportion 1972. Remote circuitry 1974 may include a remote portion of themotion control circuitry 1978 and remote portion of the responseinitiation circuitry 1980. Lumen-traveling device 1950 may includereceiver/transceiver 1984 that may include data reception and/ortransmission circuitry configured to receive a wireless control signalfrom the remote portion of the motion control circuitry 1978,transmitted from transceiver 1984. Data may be transmitted fromlumen-traveling device 1950 to remote portion 1972. Remote portion 1972may include a power source 1986. Alternatively, the motion controlcircuitry may be located in or on the lumen-traveling device. Theembodiment of FIG. 35 may include power source 1968 configured toprovide power to at least one of propelling mechanism 1956, steeringmechanism 1966, motion control circuitry 1958, sensor 1960, responseinitiation circuitry 1962 or active portion 1964. Components of theembodiment of FIG. 35 may be generally as described elsewhere herein.Steering mechanism 1966 may be as described above in connection withFIG. 34. In some embodiments, power may be transmitted tolumen-traveling device 1950 from remote portion 1972.

The motion control circuitry may be operatively connected to the sensor,and configured to control at least one of steering mechanism orpropelling mechanism to control the movement of the lumen-travelingdevice at least in part in response to receipt of the sense signalindicating detection of the condition of interest in the body lumen.Similarly, the response initiation circuitry may be located in or on thelumen-traveling device in some embodiments, while in other embodimentsat least a portion of the response initiation circuitry may be locatedremote from the lumen-traveling device, wherein the lumen-travelingdevice may include data transmission and reception circuitry configuredfor communicating with the at least a portion of the response initiationcircuitry located remote from the lumen-traveling device.

The control circuitry for the lumen-traveling device, located either onthe lumen-traveling device or in a remote portion, and includingresponse initiation circuitry and/or motion control circuitry, mayinclude a microprocessor, and/or at least one of hardware, software, orfirmware. Examples of devices and/or systems for communicating withindevices in the body are provided in U.S. Pat. No. 5,843,139; 6,409,674;or 7,125,382; U.S. Patent Application 2002/0198604, and RICE, MIKE;“Implantable Neurostimulation Device Market Poised for ExplosiveGrowth”; Future Fab International; Jan. 7, 2006; pp. 1-4; printed onOct. 6, 2006; located athttp://www.future-fab.com/documents.asp?d_ID=3725, all of which areincorporated herein by reference in their entirety.

Various embodiments of lumen-traveling devices as depicted and describedherein may include a lumen-wall-engaging portion; a fluid-contactingportion configured to contact fluid within the body lumen and to atleast intermittently permit flow of fluid through the body lumen; apropelling mechanism capable of producing movement of thelumen-traveling device through a body lumen in which the lumen-travelingdevice may be deployed; at least one sensor capable of detecting acondition of interest in the body lumen and generating a sense signalindicating detection of the condition of interest; motion controlcircuitry carried at least in part on said lumen-traveling device andconfigured to control the propelling mechanism at least in part basedupon the sense signal; response initiation circuitry operativelyconnected to the sensor and configured to generate a response initiationsignal upon receipt of the sense signal indicating detection of acondition of interest in the body lumen; and an active portionoperatively connected to the response initiation circuitry and capableof producing a response upon receipt of the response initiation signal.A fluid contacting portion configured to contact fluid within the bodylumen and at least intermittently permit flow of fluid through the bodylumen is though to be a useful feature for lumen-traveling device usedin lumens through which fluid travel, such as, for example, bloodvessels, portions of the respiratory tract, digestive tract or CSFspace. In some cases, blockage of flow may cause serious problems. Thus,lumen-traveling devices which are configured to permit the flow of fluidat least a portion of the time may be of value. For example, fluid mayflow through a channel or lumen passing through the lumen-travelingdevice (e.g., as depicted in FIG. 1, 29, or 32), or past alumen-traveling device that has an cross section that does not fill thecross-section of the lumen, as in FIG. 5A, 5E, 30A, 30B, or 33, forexample.

As shown in various of the figures, a lumen-traveling device may includea power source configured to provide power to at least one of thepropelling mechanism, the motion control circuitry, the sensor, theresponse initiation circuitry, or the active portion. The power sourcemay be located on the lumen-traveling device, or (at least in part) on aremote portion as illustrated in FIG. 35, with power being transmittedto the lumen-traveling device.

A lumen-traveling device may include various types of sensing orinformation gathering devices or structures. A lumen-traveling devicemay include one or multiple sensors of the same or different types,which may include but are not limited to, pressure sensors, temperaturesensors, flow sensors, viscosity sensors, shear sensors (e.g., formeasuring the effective shear modulus of the fluid at a frequency orstrain-rate), pH sensors, chemical sensors for determining theconcentration of a chemical compound or species, optical sensors,acoustic sensors, biosensors, electrical sensors, magnetic sensors,clocks or timers. Examples of a variety of sensor which may be used inembodiments as described herein are provided in U.S. Pat. Nos.5,522,394; 5,873,835; 6,053,837; 6,409,674; 6,111,520; 6,278,379;6,475,639; 6,855,115, and U.S. Patent Applications 2005/0277839 and2005/0149170, all of which are incorporated herein by reference. U.S.Pat. No. 6,802,811, which is included herein by reference, providesadditional examples of sensing and/or monitoring. In some embodiments,an imaging device (e.g., a CCD array) may be operatively connected tolumen-traveling device, e.g. connected to the structural element.

An optical sensor may be configured to measure the optical absorption,optical emission, fluorescence, or phosphorescence of at least a portionof the fluid, for example. Such optical properties may be inherentoptical properties of all or a portion of the fluid or tissue, or may beoptical properties of materials added or introduced to the fluid, suchas tags or markers for materials of interest. Optical sensing ofmaterials in blood is described, for example, in KRUEGER, CURTIS; “Newlight on blood testing”; Oct. 20, 2006; pp. 1-2; St. Petersburg Times;printed on Dec. 24, 2006; located athttp://www.sptimes.com/2006/10/20news_pf/Tampabav/New_light_on_blood_te.shtml,which is incorporated herein by reference.

A biosensor may detect materials including, but not limited to, abiological marker, an antibody, an antigen, a peptide, a polypeptide, aprotein, a complex, a nucleic acid, a cell (and, in some cases, a cellof a particular type, e.g. by methods used in flow cytometry), a cellfragment, a cellular component, a platelet, an organelle, a gamete, apathogen, a lipid, a lipoprotein, an alcohol, an acid, an ion, animmunomodulator, a sterol, a carbohydrate, a polysaccharide, aglycoprotein, a metal, an electrolyte, a metabolite, an organiccompound, an organophosphate, a drug, a therapeutic, a gas, a pollutant,or a tag. A biosensor may include an antibody or other binding moleculesuch as a receptor or ligand. As used herein a sensor may include asingle sensor or an array of sensors, and is not limited to a particularnumber or type of sensors. A sensor might comprise, in part or whole, agas sensor such as an acoustic wave, chemiresistant, or piezoelectricsensor, or perhaps an electronic nose. A sensor may be very small,comprising a sensor or array that is a chemical sensor (“ChemicalDetection with a Single-Walled Carbon Nanotube Capacitor,” Snow, E. S.et al., Science, Vol. 307, pp. 1942-1945, 2005), a gas sensor (“Smartsingle-chip gas sensor microsystem,” Hagleitner, C. et al., Nature, Vol.414, pp. 293-296, 2001), an electronic nose, a nuclear magneticresonance imager (“Controlled multiple quantum coherences of nuclearspins in a nanometre-scale device”, Go Yusa, 2005, Vol. 343: pp.1001-1005, Nature). The foregoing references are incorporated herein byreference. Further examples of sensors are provided in The BiomedicalEngineering Handbook, Second Edition, Volume I, J. D. Bronzino, Ed.,Copyright 2000, CRC Press LLC, pp. V-1-51-9, and U.S. Pat. No.6,802,811, both of which are incorporated herein by reference.

A sensor may be configured to measure various parameters, including, butnot limited to, the electrical resistivity of fluid, tissue, or othermaterial, the density or sound speed of a material, the pH, theosmolality, or the index of refraction of the fluid at least onewavelength. The selection of a suitable sensor for a particularapplication or use site is considered to be within the capability of aperson having skill in the art. In some embodiments, a sensor mayinclude some signal processing or pre-processing capability integratedtherewith.

The condition of interest detected by the sensor may include ananatomical feature (for example, a branching point) that indicatesproximity to a treatment target, or indicates the presence of thetreatment target itself. The condition of interest may include aman-made structure, such as an implantable device of some sort,potentially including another lumen-traveling device. Alternatively, thecondition of interest may include one or more of an electrical field,magnetic field, temperature, flow condition, time, location, pressure,pH, presence or concentration of a chemical compound or species.

A sensor may sense a wide variety of physical or chemical properties. Insome embodiments, detecting a condition of interest may includedetecting the presence (or absence) of a material or structure ofinterest.

In some applications, detecting a condition of interest in the fluidwithin the body lumen may include detecting the presence of a materialof interest in the fluid within the body lumen. A material of interestin a fluid may include, for example, an object such as a blood clot, athrombus, an embolus, a plaque, a lipid, a kidney stone, a dustparticle, a pollen particle, an aggregate, a cell, a specific type ofcell, a cell fragment, a cellular component, a platelet, an organelle, acollection or aggregation of cells or components thereof a gamete, apathogen, or a parasite.

Lumen-traveling devices may be used in a number of different ways. Insome embodiments, a lumen-traveling device may travel through the lumenperforming an action at selected locations that are identified as thedevice travels through the lumen. A device may move through the bodylumen performing “surveillance” for periods of time ranging from a fewminutes, to hours, days, weeks, or years. When the lumen-travelingdevice identifies a location of interest (e.g., a location where somesort of medical treatment is needed), it may perform an action, whichmay include delivering a medical treatment, transmitting a signalindicating the need for medical treatment to a monitoring system, orrecording information about the location of interest, for example. Alumen-traveling device performing surveillance in a body lumen mayperform an action “on the fly” as it moves past the location ofinterest, or it may pause or cease moving at or near a location ofinterest in order to perform an action.

Sensors in combination with logic circuitry (hardware, firmware, and/orsoftware) may be used to detect a condition of interest in or on thewall of the body lumen, in the tissue that forms or surrounds the bodylumen, or in the fluid within the body lumen. A location of interest ina body lumen may include a location of anatomical interest (e.g., abranching point), a location near an organ, a tumor, an injury, etc, adiseased or damaged region (e.g. a fistula or aneurysm), area of scartissue, a polyp, a blockage or constriction formed by a bacterialplaque, blood clot, or vasospasm, for example. Locations of interest maybe detected by the detection of chemical markers or fingerprints, byaltered mechanical, optical, thermal, electrical or acoustic properties,by imaging, and by other detection methods as known to those of skill inthe art. The lumen-traveling device may perform one or more actions withan active portion in response to detection of a location of interest.Tissue condition can be detected with the use of pressure pulses, asdescribed in U.S. Pat. No. 6,170,488 and U.S. Patent Applications2003/0220556 and 2004/0225325, all of which are incorporated herein byreference.

In some embodiments, a lumen-traveling device may perform an actioncontinuously or intermittently as it moves through a body lumen.Performance of the action may not necessarily always be associated withdetection of a region of interest within a body lumen.

In some embodiments, a lumen-traveling device may move through a bodylumen until it reaches a particular location and then cease traveling inorder to reside, either temporarily or substantially permanently, at thelocation. At the location, it may perform an action on the local tissueforming the lumen or perform an action on fluid within the lumen, whichmay be flowing or moving in some other manner, either continuously orintermittently, or may be substantially unmoving. The location at whicha lumen-traveling device stops and resides may be pre-selected, in whichcase the device may be targeted to the location. Alternatively, thelocation may be selected as the device is traveling through the lumen,based on one or more features of the location, which may be sensed bythe device. Features of the location may include, but are not limitedto, indicators of injuries, pathologies or disease conditions to betreated by the device, or anatomical characteristics (size, proximity toan organ or other structure, etc.) that make the location a suitablesite for the device to be positioned. Features of locations of interestmay include chemical, thermal, mechanical, optical, or other propertiesas may be sensed with various types of sensors as described elsewhereherein. A parameter may be measured at a single point in time/space ormay be measured over multiple dimensions (spatial, temporal, orother—e.g. frequency) to generate an image of a region that may includefeatures of interest. Signal processing to perform analysis of thesignal or image may be used to detect features/locations of interestfrom signal or image.

In one application, a lumen-traveling device traveling within the malereproductive tract may detect pH, flow, or viscosity of semen, forexample, and based upon the value of the detected parameter, may performan action to alter it to either enhance fertility or providecontraception.

In some embodiments, the lumen-traveling device may be used to delivertreatment to a location that is relatively inaccessible by other means.For example, a lumen-traveling device may move through vasculaturewithin the brain in order to access brain regions for delivery of drugs,therapeutics, chemotherapy agents, chemical mechanical, optical,electrical or magnetic stimuli, etc.

FIG. 36 shows steps of a method implemented with a lumen-travelingdevice. The method steps include propelling the lumen-traveling devicethrough a body lumen at step 2002; at least intermittently permittingflow of fluid through the body lumen and past a fluid-contacting portionof the lumen-traveling device at step 2004; detecting a condition ofinterest with a sensor on the lumen-traveling device at step 2006;producing a response initiation signal with response initiationcircuitry located at least in part on the lumen-traveling device atleast partially in response to detection of the condition of interest atstep 2008; and performing an action with an active portion of thelumen-traveling device in response to the response initiation signal atstep 2010.

FIG. 37 shows further variants of the method of FIG. 36. The method mayinclude propelling the lumen-traveling device through a body lumen atstep 2052; at least intermittently permitting flow of fluid through thebody lumen and past a fluid-contacting portion of the lumen-travelingdevice at step 2054; detecting a condition of interest with a sensor onthe lumen-traveling device at step 2056; producing a response initiationsignal with response initiation circuitry located at least in part onthe lumen-traveling device at least partially in response to detectionof the condition of interest at step 2058; and performing an action withan active portion of the lumen-traveling device in response to theresponse initiation signal at step 2060. In addition, propelling thelumen-traveling device through the body lumen may include propelling thelumen-traveling device with sufficient force to push open a closed bodylumen, as shown in step 2064. The step of detecting a condition ofinterest may include detecting a fluid flow, as shown in step 2066,detecting fluid viscosity as shown in step 2068, or detecting a fluidshear, as shown in step 2070.

FIG. 38 shows further variants of the method of FIG. 36. Again, themethod may include propelling the lumen-traveling device through a bodylumen at step 2102; at least intermittently permitting flow of fluidthrough the body lumen and past a fluid-contacting portion of thelumen-traveling device at step 2104; detecting a condition of interestwith a sensor on the lumen-traveling device at step 2106; producing aresponse initiation signal with response initiation circuitry located atleast in part on the lumen-traveling device at least partially inresponse to detection of the condition of interest at step 2108; andperforming an action with an active portion of the lumen-travelingdevice in response to the response initiation signal at step 2110. Inaddition, the method may include performing the action with the activeportion of the lumen-traveling device in response to the responseinitiation signal while propelling the lumen-traveling device throughthe body lumen, as shown in step 2114. Alternatively, the method mayinclude performing the action with the active portion of thelumen-traveling device in response to the response initiation signalsubsequent to stopping movement of the lumen-traveling device in thevicinity of the condition of interest, as shown in step 2116.

FIGS. 39A and 39B show further variations of the method of FIG. 36. Thebasic steps of the method include propelling the lumen-traveling devicethrough a body lumen at step 2152; at least intermittently permittingflow of fluid through the body lumen and past a fluid-contacting portionof the lumen-traveling device at step 2154; detecting a condition ofinterest with a sensor on the lumen-traveling device at step 2156;producing a response initiation signal with response initiationcircuitry located at least in part on the lumen-traveling device atleast partially in response to detection of the condition of interest atstep 2158; and performing an action with an active portion of thelumen-traveling device in response to the response initiation signal atstep 2160. Detecting a condition of interest with a sensor on thelumen-traveling device may include detecting a concentration of achemical compound or species (at step 2164), detecting an opticalparameter (at step 2166), detecting an acoustic parameter (at step2168), detecting a biomolecule with a biosensor (at step 2170),detecting an electrical parameter (at step 2172), detecting a magneticparameter (at step 2174), detecting a pressure in the body lumen (atstep 2176), or detecting a temperature in the body lumen (at step 2178),as shown in FIG. 39A, or, as shown in FIG. 39B, detecting a pH in thebody lumen (at step 2180), detecting an anatomic feature (at step 2182),detecting a location (at step 2184), detecting a man-made structure (atstep 2186), or detecting a time (at step 2188). If a man-made structureis detected, as at step 2186, the method may include the steps ofdelivering a material or structure to the man-made structure (at step2190), receiving a material or structure from the man-made structure (atstep 2192), or collecting the man-made structure (at step 2194). Thismay, for example, involve connecting to the man-made structure so thatit can be pushed or pulled by the lumen-traveling device, or may involvetaking up the man-made structure to be contained in or carried withinthe lumen-traveling device.

Steps 40A-40E show further variants of a method as described generallyin FIG. 36. Again, the method may include propelling the lumen-travelingdevice through a body lumen at step 2252; at least intermittentlypermitting flow of fluid through the body lumen and past afluid-contacting portion of the lumen-traveling device at step 2254;detecting a condition of interest with a sensor on the lumen-travelingdevice at step 2256; producing a response initiation signal withresponse initiation circuitry located at least in part on thelumen-traveling device at least partially in response to detection ofthe condition of interest at step 2258; and performing an action with anactive portion of the lumen-traveling device in response to the responseinitiation signal at step 2260. As shown in FIG. 40A, the step ofperforming an action with the active portion (at step 2260) may includetransmitting a signal to a remote location (at 2264), releasing amaterial (at step 2266), which may be, for example, at least one of anadhesive, a filler, a hydrogel, an antibiotic, a pharmaceuticalcompound, a nutrient, a hormone, a growth factor, a medication, atherapeutic compound, an enzyme, a protein, a genetic material, a cell,a fraction of a cell, a vaccine, a vitamin, a neurotransmitter, aneurotropic agent, a neuroactive material, a cytokine, a cell-signalingmaterial, a pro-apoptotic agent, an anti-apoptotic agent, animmunological mediator, an anti-inflammatory agent, a salt, an ion, anantioxidant, an imaging agent, a labeling agent, a diagnostic compound,a nanomaterial, an inhibitor, or a blocker (as indicated at step 2268).Alternatively, as shown in FIG. 40B, performing an action with theactive portion may include collecting a material from the body lumen (asshown in step 2270), which may include collecting a sample from a fluidwithin the body lumen (as shown in step 2272), or collecting a samplefrom a wall region of the body lumen (as shown in step 2274).Alternatively, the method may include collecting a sample from beyondthe wall region of the body lumen, e.g., with the use of a needle topenetrate the body lumen wall and/or utilizing a permeation enhancer.

In some versions of the method, as shown in FIG. 40B, performing anaction with the active portion may include producing heating or cooling,as shown in steps 2276 and 2282, respectively. Heating may be used in avariety of locations, for a variety of purposes. In one example, themethod may include propelling the lumen-traveling device through thebody lumen to a location in the vicinity of the preoptic area, whereinperforming an action with the active portion may include producingheating in the vicinity of the preoptic area, as shown in step 2278. Inanother example, heating may be used in the male reproductive system todestroy gametes, as shown in step 2280. In another example (not shown),heating may be used for ablation of tissue. In addition, oralternatively, performing an action with the active portion may includesecuring the lumen-traveling device into position within the body lumenas shown in step 2284, e.g., by using various positioning orlumen-wall-engaging structures.

As shown in FIG. 40C, in some embodiments, performing an action with theactive portion may include emitting electromagnetic radiation, as shownat step 2286. The action may include emitting ultraviolet, infrared,optical, microwave, or millimeter wave electromagnetic radiation, asindicated at steps 2288, 2290, 2292, 2294, and 2296, respectively.Alternatively, as shown in step 2298 of FIG. 40D, performing an actionwith the active portion may include emitting acoustic energy, including,but not limited to, ultrasonic acoustic energy, as indicated in step2300. As shown in FIG. 40D, performing an action with the active portionmay include applying pressure to the body lumen (step 2302), byexpansion of the active portion, or by release of a gas or fluid. Inother embodiments, performing an action with the active portion mayinclude modulating the flow of fluid through at least a portion of thebody lumen, as shown at step 2304, for example by blocking the flow offluid through at least a portion of the body lumen (step 2306),modifying the direction of flow of fluid through at least a portion ofthe body lumen (2308), or modifying the amount of turbulent flow (step2310). Modifying the direction of flow of fluid may include directingflow, toward a particular region and/or into a particular branch of abranching lumen, for example, with the use of various flow-directingstructures as disclosed herein. Modifying the direction of flow of fluidmay also include reversing the direction of flow, which may beaccomplished, for example, by modifying the pressure within the lumen,as described herein.

As shown in FIG. 40E, in some embodiments, performing an action with theactive portion at step 2260 may include at least partly removingspecific components from at least a portion of a fluid within the bodylumen, as shown at step 2312, or activating at least one catalyst, asshown at step 2314. In still other embodiments, performing an actionwith the active portion may include generating an electric field, asshown at step 2316, generating a magnetic field, as shown at step 2318,or scraping or cutting at least a portion of the body lumen, asindicated at steps 2320 and 2322, respectively. Performing an actionwith the active portion may include releasing a man-made structure fromthe lumen-traveling device, as shown at step 2324, and, in someembodiments, attaching the man-made structure to a wall of the bodylumen, as shown at step 2326. As shown in FIG. 40F, performing an actionwith the active portion at step 2260 may include delivering a materialor structure to a receiving portion of a man-made device, as shown at2328, receiving a material or structure from a delivery portion of aman-made device, as shown at 2330. Finally, the method may include oneor more of transmitting power to the lumen-traveling device, as shown instep 2332, transmitting a signal to the lumen-traveling device, as shownin step 2334, receiving a signal from a remote source with thelumen-traveling device, as shown in step 2336, or receiving power from aremote source with the lumen-traveling device, as shown in step 2338.

A lumen-traveling device as described herein may include controlcircuitry for controlling various aspects of the operation of thedevice. Lumen-traveling devices and systems as described herein may beoperated under the control of control circuitry, which may includehardware, software, firmware, or a combination thereof.

FIG. 41 is a block diagram illustrating in greater detail variouscircuitry components of a lumen-traveling system. As discussed elsewhereherein, the circuitry components may be located entirely on thestructural element of a lumen-traveling device, or may be distributedbetween the lumen-traveling device and a remote portion. Thelumen-traveling system may include one or more sensors 2400 formeasuring or detecting a condition of interest. Sensing circuitry 2402may be associated with sensors 2400. The lumen-traveling system mayinclude various control circuitry 2404, including response initiationcircuitry 2406. Response initiation circuitry 2406 may provide aresponse initiation signal to active portion 2408. Control circuitry2404 may also include data storage portion 2412, which may, for example,be used to store pattern data 2414 or pattern variables 2416 fordetermining an activation pattern of active portion 2408. Data storageportion 2412 may also store positional information, including, forexample, the current device position or the position of one or moretarget locations or landmarks, or a map of some or all of the relevantbody lumen(s) of the subjects. In some embodiments, control circuitry2404 may include motion control circuitry 2418 for controllingpropelling mechanism 2420, and optionally steering mechanism 2422.Control circuitry may include transceiver circuitry 2424, which providesfor the transmission and reception of data and/or power signals betweenthe lumen-traveling device and one or more remote portion or externaldevices (e.g., monitoring or recording equipment). A user input portion2426 may provide for the input of user instructions, parameter, etc. tocontrol circuitry 2404. Finally, one or more power source 2428 mayprovide power to electrical components of the lumen-traveling system.Some components of the lumen-traveling device may be operated in wholeor in part under software control, and control circuitry 2404 mayinclude hardware, software, hardware, or various combinations thereof.The lumen-traveling device may include components that may be primarilyhardware-based, e.g., sensor 2400, active portion 2408, propellingmechanism 2420, steering mechanism 2422, and, optionally, user inputdevice 2426. Hardware-based devices may include components that areelectrical, mechanical, chemical, optical, electromechanical,electrochemical, electro-optical, and are not limited to the specificexamples presented herein. As described elsewhere, in some embodiments,portions of the control circuitry, including, for example, the responseinitiation circuitry, may be located in or on the structural element,while in other embodiments the response initiation circuitry may be at alocation remote from the structural element.

In many embodiments, the control circuitry as depicted in FIG. 41 may beimplemented in the form of logic, for example software or digital logiccircuitry. FIG. 42 depicts modules of logic (which may be software orhardware) which may be used in the control of lumen-traveling devices asdescribed herein. As shown in FIG. 42, logic 2500 for controlling alumen-traveling device, may include, for example, a sensing module 2502capable of processing an input from a sensor 2504 on the lumen-travelingdevice to generate a sense signal indicating detection of a condition ofinterest in a body lumen of an organism; a response initiation module2506 capable of receiving the sense signal from the sensing module 2502and based at least in part upon the sense signal generating a responseinitiation signal configured for causing an action to be performed inthe body lumen by an active portion 2508 of the lumen-traveling device;and a motion control module 2510 capable of controlling at least one ofa propelling mechanism 2512 or a steering mechanism 2514 on thelumen-traveling device to control direction or rate of movement of thelumen-traveling device through the body lumen. The logic may beimplemented in digital circuitry, analog circuitry, software, orcombinations thereof. The motion control module 2510 may be capable ofreceiving the sense signal from the sensing module 2502 and controllingat least one of the propelling mechanism 2512 or the steering mechanism2514 on the lumen-traveling device based at least in part upon the sensesignal. In one alternative embodiment, as shown in FIG. 43, the motioncontrol 2510 module may be capable of controlling at least one of thepropelling mechanism 2512 or steering mechanism 2514 on thelumen-traveling device based at least in part upon a motion controlsignal from a remote portion 2520. Otherwise, the logic 2550 is likethat shown in FIG. 42, including sensing module 2502 capable ofprocessing an input from a sensor 2504 on the lumen-traveling device togenerate a sense signal indicating detection of a condition of interestin a body lumen of an organism; a response initiation module 2506capable of receiving the sense signal from the sensing module 2502 andbased at least in part upon the sense signal generating a responseinitiation signal configured for causing an action to be performed inthe body lumen by an active portion 2508 of the lumen-traveling device;and a motion control module 2510 capable of controlling at least one ofa propelling mechanism 2512 or a steering mechanism 2514 on thelumen-traveling device to control direction or rate of movement of thelumen-traveling device through the body lumen. In another relatedembodiment, motion control module 2510 may be capable of controlling atleast one of propelling mechanism 2512 or the steering mechanism 2514 onthe lumen-traveling device based at least in part upon a pre-programmedmotion pattern, for example a motion pattern stored in a data storagelocation 2412 as data storage location 2412 in FIG. 41. In someembodiments, sensing module 2502 may be capable of generating a sensesignal indicating the presence or absence of the condition of interest,wherein response initiation module 2506 may be capable of generating aresponse initiation signal configured for initiating the performance ofthe action in the body lumen by active portion 2508 of thelumen-traveling device. Response initiation module 2506 may includecontrol logic that uses a pre-programmed pattern which may be stored ina memory location on the lumen-traveling device (again, like datastorage location 2412 in FIG. 41).

In some embodiments, sensing module 2502 may be capable of generating asense signal indicating the presence or absence of the condition ofinterest, and response initiation module 2506 may be capable ofgenerating a response initiation signal configured for controlling theperformance of the action in the body lumen by the active portion of thelumen-traveling device in a pre-programmed pattern. In some embodiments,the sensing module may be capable of generating a sense signalindicating a parameter value of the condition of interest, wherein theresponse initiation module may be capable of generating a responseinitiation signal configured for initiating the performance of theaction in the body lumen by the active portion 2508 of thelumen-traveling device as a function of the parameter value of thecondition of interest. In addition, response initiation module 2506 mayin some embodiments be capable of generating a response initiationsignal configured for controlling the action by the active portion 2508of the lumen-traveling device for a period of time as a function of theparameter value of the condition of interest. In some embodiments,sensing module 2502 may be capable of generating a time-varying sensesignal indicating a time-varying parameter value of the condition ofinterest, wherein the response initiation module 2506 may be capable ofgenerating a response initiation signal configured for controllingactive portion 2508 of the lumen-traveling device as a function of thetime-varying sense signal.

FIG. 44 illustrates a method of using a lumen-traveling device, whichincludes moving a self-propelling lumen-traveling device through a bodylumen at step 2602; at least intermittently permitting flow of fluidthrough the body lumen and past a fluid-contacting portion of thelumen-traveling device at step 2604; detecting a treatment target basedat least in part upon detection of a condition of interest in the bodylumen with a sensor on the lumen-traveling device at step 2606;producing a response initiation signal at least in part in response todetection of the condition of interest with response initiationcircuitry located at least in part on the lumen-traveling device at step2608; and delivering a treatment to the treatment target with an activeportion of the lumen-traveling device in response to the responseinitiation signal at step 2610.

FIG. 45 shows an expanded version of the method of FIG. 44, includingthe steps of moving a self-propelling lumen-traveling device through abody lumen at step 2652; at least intermittently permitting flow offluid through the body lumen and past a fluid-contacting portion of thelumen-traveling device at step 2654; detecting a treatment target basedat least in part upon detection of a condition of interest in the bodylumen with a sensor on the lumen-traveling device at step 2656;producing a response initiation signal at least in part in response todetection of the condition of interest with response initiationcircuitry located at least in part on the lumen-traveling device at step2658; and delivering a treatment to the treatment target with an activeportion of the lumen-traveling device in response to the responseinitiation signal at step 2660, and also including a further step 2664of stopping movement of the lumen-traveling device through the bodylumen upon detection of the treatment target and delivering thetreatment to the treatment target with the active portion of thelumen-traveling device while the lumen-traveling device may besubstantially immobile in the body lumen. A further method step 2666 mayinclude resuming movement of the lumen-traveling device through the bodylumen following delivery of the treatment to the treatment target withthe active portion of the lumen-traveling device.

FIG. 46 shows a further variation of the method of FIG. 44, includingmoving a self-propelling lumen-traveling device through a body lumen atstep 2702; at least intermittently permitting flow of fluid through thebody lumen and past a fluid-contacting portion of the lumen-travelingdevice at step 2704; detecting a treatment target based at least in partupon detection of a condition of interest in the body lumen with asensor on the lumen-traveling device at step 2706; producing a responseinitiation signal at least in part in response to detection of thecondition of interest with response initiation circuitry located atleast in part on the lumen-traveling device at step 2708; and deliveringa treatment to the treatment target with an active portion of thelumen-traveling device in response to the response initiation signal atstep 2710, where delivering the treatment to the treatment target mayinclude delivering the treatment to the treatment target as thelumen-traveling device moves past the treatment target, as shown in step2712.

In some embodiments of methods as illustrated in FIGS. 44, 45, and 46, amethod of using a lumen-traveling device may include delivering thetreatment to the treatment target with an active portion of thelumen-traveling device, wherein the treatment may be determined based atleast in part upon at least one sensed parameter of the treatmenttarget. In other embodiments, the treatment may be determined at leastin part by a treatment pattern stored in the lumen-traveling device.

In some cases, the treatment target may include at least a portion of awall of the body lumen, or in some cases, the treatment target may liebeyond the wall of the body lumen, so that delivering a treatment to thetreatment target with an active portion of the lumen-traveling device inresponse to the response initiation signal may include delivering atreatment to the treatment target through a wall of the body lumen. Insome cases, the treatment target may include at least a portion of thecontents of the body lumen.

A further method of using a lumen-traveling device, as outlined in FIG.47, may also include emplacing the lumen-traveling device in the bodylumen by inserting a catheter carrying the lumen-traveling device intothe body lumen and releasing the lumen-traveling device from thecatheter, at step 2752, followed by the steps of moving aself-propelling lumen-traveling device through a body lumen at step2754; at least intermittently permitting flow of fluid through the bodylumen and past a fluid-contacting portion of the lumen-traveling deviceat step 2756; detecting a treatment target based at least in part upondetection of a condition of interest in the body lumen with a sensor onthe lumen-traveling device at step 2758; producing a response initiationsignal at least in part in response to detection of the condition ofinterest with response initiation circuitry located at least in part onthe lumen-traveling device at step 2760; and delivering a treatment tothe treatment target with an active portion of the lumen-travelingdevice in response to the response initiation signal at step 2762. Amethod of using a lumen-traveling device may optionally includeretrieving the lumen-traveling device from the body lumen by inserting acatheter into the body lumen and withdrawing the catheter from the bodylumen carrying the lumen-traveling device, for example as shown in step2764 of FIG. 47.

In some embodiments of a method of using a lumen-traveling device, asshown in FIGS. 48A-48C, a primary lumen-traveling device 2802 and asecondary lumen-traveling device 2810 may be used. In some embodimentsof a method, e.g., as outlined in FIG. 44, the self-propellinglumen-traveling device may be a secondary lumen-traveling device 2810,and the method may include emplacing secondary lumen-traveling device2810 in the body lumen by releasing the secondary lumen-traveling device2810 from a primary lumen-traveling device 2802. In FIG. 48A, primarylumen-traveling device 2802 is located in body lumen 2800 near branchpoint 2804, where body lumen 2800 branches into smaller branch lumens2806 and 2808. Secondary lumen-traveling device 1820 is carried byprimary lumen-traveling device 2802, attached by retaining portions 2812and 2814. Primary lumen-traveling device 2802 is propelled through bodylumen 2800 (in this example, with lumen-wall-engaging structures 2816,2818, 2820, and 2821). As shown in FIG. 48B, when primarylumen-traveling device 2802 reaches branch point 2804, it may stop andrelease secondary lumen-traveling device 2810. Secondary lumen-travelingdevice 2810 may be smaller than the primary lumen-traveling device 2802,for example to permit it to travel into a smaller body lumen than theprimary lumen-traveling device will fit into, such as branch lumen 2806.Secondary lumen-traveling device 2810 may include lumen-wall-engagingstructures 2822, 2824, 2826, and 2828, which operate to propel it downbranch lumen 2806 and away from primary lumen-traveling device 2802. Asillustrated in FIG. 48C, primary lumen-traveling device may leave branchpoint 2804 after releasing secondary lumen-traveling device 2810.

Primary lumen-traveling device 2802 and secondary lumen-traveling device2810 may be substantially similar in design, but of different sizes, asdepicted in FIGS. 48A-48C. In some embodiments of a method as outlinedin FIG. 44, a self-propelling lumen-traveling device (as recited in themethod of FIG. 44) may be a primary lumen-traveling device as depictedin FIG. 48, and the method may include emplacing a secondarylumen-traveling device in the body lumen by releasing the secondarylumen-traveling device from the primary lumen-traveling device. Asdepicted in FIG. 48, the secondary lumen-traveling device may be smallerthan the primary lumen-traveling device.

FIG. 49 shows a method which includes moving a self-propellinglumen-traveling device through a body lumen at step 2902; at leastintermittently permitting flow of fluid through the body lumen and pasta fluid-contacting portion of the lumen-traveling device at step 2910;detecting a treatment target based at least in part upon detection of acondition of interest in the body lumen with a sensor on thelumen-traveling device at step 2912; producing a response initiationsignal at least in part in response to detection of the condition ofinterest with response initiation circuitry located at least in part onthe lumen-traveling device at step 2914; and delivering a treatment tothe treatment target with an active portion of the lumen-travelingdevice in response to the response initiation signal at step 2916. Inaddition, the method of FIG. 49 may include moving the lumen-travelingdevice through the body lumen at least partially under control of aremote portion, e.g., of the type illustrated in FIG. 35, as indicatedat step 2904. For example, a motion control signal may be transmitted tothe lumen-traveling device with the remote portion. The motion controlsignal may be generated with the remote portion. The motion controlsignal may be received from a remote portion with a signal receiver inthe lumen-traveling device. The method may also include transmitting asignal indicative of detection of a condition of interest from thelumen-traveling device to a remote location, or transmitting a signalindicative of performance of an action by the lumen-traveling device toa remote location.

Alternatively, as shown in FIG. 49, step 2906, a method of using alumen-traveling device may include controlling movement of thelumen-traveling device through the body lumen with a steering controlportion on the lumen-traveling device. It should be noted that in someembodiments, propulsion may be provided without steering. In someembodiments, movement of the lumen-traveling device through the bodylumen may be controlled based at least in part upon a detected conditionof interest in the body lumen, controlled based at least in part on theuse of logic circuitry included in the lumen-traveling device, and/orcontrolled based at least in part on a movement pattern stored in thelumen-traveling device. In another alternative, the lumen-travelingdevice may be moved through the body lumen in a substantially random orpseudo-random pattern, as indicated in FIG. 49, step 2908.

In this and other embodiments of methods disclosed herein, detecting acondition of interest may include detecting a variety of conditions,including but not limited to, an embolism, a plaque, a thrombus, ananeurysm, a stenosis, a puncture, a perforation, a rupture, adissection, a tear, or a branching point in the body lumen, thebranching point including at least two branches of the body lumen. Theterm “condition”, as used herein, may refer to normally occurringanatomic features, man-made or other foreign structures, features, orconditions, disease states or injuries that may be present in a lumen bychance or purpose, and various detectable or measurable characteristicsor parameters that indicate the presence of such conditions or features.In some embodiments, the method may include detecting a branching pointin the body lumen, the branching point including at least two branchesof the body lumen; the method may then also include steering thelumen-traveling device into a selected one of the at least two branchesof the body lumen.

Several additional examples of embodiments of lumen-traveling devicesare now provided, to further illustrate use of lumen-traveling devicesas described herein.

FIGS. 50A and 50B depict lumen-traveling device 3000 moving through abody lumen 3002. Lumen-traveling device 3000 includes sensor 3006,response initiation circuitry 3010, and active portion 3012.Lumen-traveling device 3000 also includes motion control circuitry 3014.As shown in FIG. 50A, sensor 3000 detects a location of interest—in thiscase, material 3008 on the wall 3004 of body lumen 3002. Material 3008may be, for example, a plaque on the wall of an artery. Sensor 3006 maybe an optical sensor, an imaging device, or various other types ofsensors, as are known to those of skill in the art. Upon detection ofmaterial 3008, active portion 3012 may be an activated, as shown in FIG.50B. In this example active portion 3012 performs ablation of material3008; for example, active portion 3012 may be an optical device whichgenerates light to perform, for example, laser ablation of a plaque, orit may be an acoustic device for performing ultrasonic ablation of aplaque.

FIGS. 51A and 51B depict a lumen-traveling device 3050 moving through alumen 3052 that is constricted, e.g. by a vasospasm. Lumen 3052 isdefined by lumen walls 3054, which at vasospasm 3056 are constricted,blocking the flow of fluid through the lumen. Lumen-traveling device3050 includes sensor 3058, which detects the presence of the vasospasm,for example, by detecting reduced flow of fluid through the body lumen.Lumen-traveling device 3050 also includes material release structure3060, which may be activated in response to detection of vasospasm 3056,to release a vasoactive substance 3064 to produce relaxation of thevasospasm, as illustrated in FIG. 51B. Lumen-traveling device 3050 mayalso include propelling mechanism 3062, as well as other components notdepicted in FIGS. 51A and 51B, but as described elsewhere herein.

FIGS. 52A and 52B illustrate a further example of a lumen-travelingdevice 3100 traveling through a body lumen 3102. Body lumen 3102includes an aneurysm 3104, which may be detected by sensor 3106 onlumen-traveling device 3100. A sense signal generated by sensor 3106causes response initiation circuitry 3108 to cause activation of activeportions 3110 and 3112 to engage walls 3114 of body lumen 3102 to sealoff aneurysm 3104 and cause fluid to flow through central lumen 3116 oflumen-traveling device 3100, rather than into aneurysm 3104.

FIGS. 53A and 53B illustrate the treatment of a fluid flowing through alumen-traveling device 3150 positioned in a body lumen 3152. Thelumen-traveling device 3150 may move to a location of interest throughthe use of propelling mechanism 3157, for example, and then engage thelumen walls to remain in the location of interest and treat fluid movingthrough it. Alternatively, lumen-traveling device 3150 may treat fluidas it moves through body lumen 3152, including fluid residing in orflowing through the lumen-traveling device. Body lumen 3152 is definedby wall portions 3154. In FIG. 53A, component 3164 of fluid flowingthrough body lumen 3152 is detected by sensor 3158 in structural element3156 of lumen-traveling device 3150. Upon detection of component 3164 bysensor 3158, a sense signal 3159 is sent to response initiationcircuitry 3160, which generates a response initiation signal 3161.Response initiation signal 3161 is sent to active portion 3162. As shownin FIG. 53B, upon receipt of response initiation signal 3161, activeportion 3162 produces a response or action, which in this example is apulse of energy (e.g. acoustic energy) to destroy component 3164(indicated following destruction by reference number 3164′). Forexample, a pulse of acoustic energy may be used to modify a kidney stonein the urinary tract, or to modify another object in another body fluid.

In connection with detection of the presence of a material, location, orother condition(s) of interest within or near the body lumen or thelumen contents, the active portion of the lumen-traveling device orsystem may be capable of removing, modifying, or destroying a materialof interest or treating a location of interest. Modification ordestruction of the material of interest may be accomplished by therelease of a suitable material (e.g. an anti-coagulant for destroying ablood clot, complement to coat a parasite for recognition by the immunesystem, or by the release of an anti-inflammatory, biomimetic orbiologic to bind to and inactivate an inflammatory mediator such asTNFα, by the delivery of suitable energy (e.g., acoustic energy formodifying a kidney stone, electromagnetic energy such as light to causea photoreaction, break bonds in a molecule, produce heating,vaporization, ablation, etc., or by delivery of heat or cold or otherchemo-physical change (e.g. ambient pressure, pH, osmolality, toxicmaterial introduction/generation) for tissue modification, as inablation of circulating tumor cells or plaque or temperature-inducedmodification of sperm as it passes through the vas deferens.

In some embodiments of lumen-traveling devices or systems, alumen-traveling device may be a self-contained device that includes allfunctionalities necessary for operation of the device. In otherembodiments, as illustrated in FIG. 28, 35 or 43, a lumen-travelingsystem may include a lumen-traveling device that may be placed in a bodylumen, and a remote portion that includes a portion of thefunctionalities of the lumen-traveling system. In some embodiments, allfunctionalities essential for the operation of the lumen-travelingdevice may be located on the lumen-traveling device, but certainauxiliary functions may be located in the remote portion. For example,the remote portion may provide monitoring of the operation of thelumen-traveling device or data collection or analysis. The remoteportion may be located within the body of the subject at a distance fromthe lumen-traveling device, or outside the body of the subject, asdepicted in FIG. 28. The remote portion may be located near the subject(e.g., carried or worn on the subject's body or placed on a table nearthe subject) or distant from the subject (e.g. in a different room orbuilding, or in a different city, state or country). Data and/or powersignals may be transmitted between lumen-traveling device and remoteportion with the use of electromagnetic or acoustic signals, or, in someembodiments, may be carried over electrical or optical links. Varioustypes and/or combinations of types of communications methods and devicesmay be used, as are known to those of skill in the art. In someembodiments, transmission of information between the lumen-travelingdevice and one or more remote portions may be via multiple communicationchannels, in series or in parallel. In general, the remote portion maybe placed in a location where there is more space available than withinthe body lumen, or that is more readily accessible than the body lumen.It is contemplated that a portion of the electrical circuitry portion ofthe lumen-traveling system (which may include hardware, firmware,software, or any combination thereof) may be located in a remoteportion.

Methods of distributing functionalities of a system between hardware,firmware, and software located at two or more sites are well known tothose of skill in the art. An electrical circuitry portion of thelumen-traveling system may include, but is not limited to, electricalcircuitry associated with the sensor, response initiation circuitry, andelectronics associated with the active portion. While the responseinitiation circuitry has been discussed within the context of electricalcircuitry, it will be appreciated that in some embodiments other typesof logic/circuitry may be used in place of or in addition to electricalcircuitry, and the response initiation circuitry and other circuitrydescribed herein is not limited to electrical circuitry. For example,fluid circuitry, chemo-mechanical circuitry, and other types oflogic/circuitry may provide equivalent functionality and may be used incertain embodiments.

In some embodiments, the lumen-traveling device may include an externalsteering system capable of transmitting a wireless control signal to thestructural element. In some embodiments, the lumen-traveling device mayinclude a steering control portion in or on the structural element.Either the steering control portion in or on the structural element oran external steering system may be operated in a number of ways.

A lumen-traveling device may include an imaging marker or tag, and theremote portion may include an external imaging system or be capable ofreceiving information from an external imaging system. The position ofthe lumen-traveling device may be correlated with a pre-existing map ofthe body of the subject, or used to construct a map of the body of thesubject. Movement of the lumen-traveling device may be controlled basedat least in part upon the location of the lumen-traveling device withinthe body of the subject. In some embodiments, the lumen-traveling devicemay include a data storage location in which a map of the body of thesubject may be stored. A pre-existing map may be stored in the datastorage location before the lumen-traveling device is introduced intothe body lumen of the subject. Alternatively, a map may be generated,either with the use of logic on the device or in a remote system, on thebasis of information gathered as the device travels through the body ofthe subject, and the map thus generated may be stored in a memorylocation on the lumen-traveling device or elsewhere. In someembodiments, rather than storing a map, other positional or locationalinformation may be stored that may be used to control the route takenthrough the body by the lumen-traveling device. In some embodiments, itmay be desired that the device covers some statistical distribution oflumen sizes or locations during its travels, but it may not be necessarythat it travel a specific route through the body, and size and locationinformation for already-visited sites may be stored and used inselection of the route to be taken by the device.

FIG. 54 illustrates an embodiment of a lumen-traveling device 3900 thatincludes a propelling mechanism 3902 capable of producing directionalmovement of the lumen-traveling device 3900 through a body lumen; asteering mechanism 3904 capable of modifying a direction of movement ofthe lumen-traveling device; at least one electromagnetic transducer 3906configured for at least one of producing an output signal representativeof a bioelectromagnetic signal sensed from a target tissue or deliveringan electromagnetic stimulus to the target tissue; and at least one of asignal processing portion 3908 capable of processing the output signalfrom the electromagnetic transducer or a stimulus source 3910 capable ofproducing an electromagnetic stimulus for delivery to the target tissuewith the at least one electromagnetic transducer. As used herein, theterm “bioelectromagnetic signal” refers to a signal that is anelectrical, magnetic, and/or electromagnetic signal (or combinationthereof) that is biological in original, for example as may be detectedfrom neural tissue, cardiac tissue, and various other body tissues, asis known by those of skill in the art. Bioelectromagnetic signals areconsidered to include electrical and ionic currents, potentials, and/orcharges, magnetic fields, fluxes, static and quasi-staticelectromagnetic fields, for example. A biological signal source maygenerate both electric and magnetic fields, either or both of which maybe detected, and which may in some cases may be related. See J. Malmivuoand R. Plonsey, Bioelectromagnetism: Principles and Applications ofBioelectric and Biomagnetic Fields, Oxford University Press, NY, 1995(Web Version), http://butler.cc.tut.fi/˜malmivuo/bem/bembook/, which isincorporated by reference in its entirety; in particular, chapters 11and 12 discuss the theory underlying bioelectric and biomagneticmeasurements, respectively, chapters 13 and 14 discuss electric andmagnetic measurements of electric activity of neural tissue, andchapters 15-20 discuss electric and magnetic measurements of theelectric activity of the heart.

The lumen-traveling device may include at least one wall-engagingstructure capable of engaging a wall of the body lumen to secure thelumen-traveling stimulation device with respect to the wall of the bodylumen in the vicinity of a target tissue. A wall-engaging structure maybe, for example, an expanding or extending structure, or a structurethat engages the lumen wall through other mechanisms, such as suctionmechanisms, adhesives, claws or hooks, as described elsewhere herein.

The lumen-traveling device may include a structural element configuredto at least intermittently permit the movement of fluid through the bodylumen past the lumen-traveling device. In some cases the structuralelement may permit continuous or near continuous flow of fluid past thelumen-traveling devices, while in others the device may permit fluidmovement at some times and obstruct fluid movement at other times, in acontrolled and/or predictable manner. The structural element may be adescribed herein in connection with FIGS. 2A-2D, 3A-3C, and elsewhereherein.

In some embodiments, as illustrated in FIG. 55, the lumen-travelingdevice 3950 may be configured for recording, and this in addition to apropelling mechanism 3952 capable of producing directional movement ofthe lumen-traveling device 3950 through a body lumen; a steeringmechanism 3954 capable of modifying a direction of movement of thelumen-traveling device, which may include at least one electromagnetictransducer 3956 configured for producing an output signal representativeof a bioelectromagnetic signal sensed from a target tissue, and at leastone signal processing portion 3958 capable of processing thebioelectromagnetic signal recorded from the target tissue with the atleast one electromagnetic transducer. Lumen-traveling device 3950 mayalso include a data storage location 3960, or other structure forstoring the sensed signal. Alternatively, lumen-traveling device 3950may include a transmitter for transmitting the sensed signal to a remotelocation.

In other embodiments, as illustrated in FIG. 56, the lumen-travelingdevice 4000 may be configured for stimulation, including a propellingmechanism 4002, steering mechanism 4004, at least one electromagnetictransducer 4006 configured for delivering an electromagnetic stimulus tothe target tissue, and at least one stimulus source 4008 capable ofproducing an electromagnetic stimulus for delivery to the target tissuewith the at least one electromagnetic transducer.

FIG. 57 depicts a version of a lumen-traveling device 4100 that isconfigured to perform both stimulation and recording. FIG. 57 alsodepicts and describes additional components that may be included invarious embodiments of lumen-traveling biological interface devices thatperform only stimulation or only recording, for example as depicted insimplified schematic form in FIGS. 54, 55, and 56. Lumen-travelingdevice 4100 may include at least one electromagnetic transducer 4102configured for producing an output signal representative of abioelectromagnetic signal sensed from a target tissue (in this exampletwo electromagnetic transducers 4102 are depicted, but one or largernumbers of electromagnetic transducers may be used for sensing), atleast one electromagnetic transducer 4104 configured for delivering anelectromagnetic stimulus to the target tissue (again, in this exampletwo electromagnetic transducers for delivering stimuli are depicted, butone or a larger number of electromagnetic transducers for stimulationmay be used), at least one signal processing portion 4106 capable ofprocessing the output signal from the electromagnetic transducer 4102,and at least one stimulus source 4108 capable of producing anelectromagnetic stimulus for delivery to the target tissue with the atleast one electromagnetic transducer 4104. In some embodiments, thelumen-traveling device 4100 may include at least one electromagnetictransducer that is configured for both producing an output signalrepresentative of a bioelectromagnetic signal sensed from a targettissue and delivering an electromagnetic stimulus to the target tissue;i.e. a single electromagnetic transducer may perform both recording orstimulating functions. In other embodiments, separate structures areused for recording and stimulating. Separate structures may be of thesame or different types. Although FIG. 57 illustrates two transducersfor recording and two transducers for stimulating, it is contemplatedthat a single lumen-traveling device may include larger numbers ofelectromagnetic transducers, which may be used for one or both ofrecording or stimulation. Naturally, the electronic circuitry associatedwith the transducers may be modified appropriately; for example, variousmultiplexing schemes, as known to those of skill in the art, may be usedfor handling input to and output from multiple transducers. As describedpreviously, lumen-traveling device 4100 may include a propellingmechanism 4110 and steering mechanism 4112. A lumen-traveling device4100 may also include a receiver 4114 configured to receive a signalfrom a remote portion 4116. Lumen-traveling device 4100 may include atransmitter 4118 configured to transmit a signal to a remote device. Theremote device may be a controller (e.g. remote portion 4116 shown inFIG. 57) or any device that detects, records, and/or re-transmits datafrom lumen-traveling device 4100. Remote portion 4116 may include remotecircuitry 4122, transmitter 4124, and receiver 4126, and may includeother components, for example as depicted in connection with FIG. 34.Control circuitry 4120 on lumen-traveling device 4100 may also includeadditional components, as described generally elsewhere herein, e.g. inconnection with FIG. 34.

The lumen-traveling device may include a sensor 4128 capable of sensinga parameter indicative of proximity to the target tissue and generatinga sense signal, which may be, for example, an optical sensor, an imagingdevice, a thermal sensor, a chemical sensor, an electrical or a magneticsensor or other sensors as described elsewhere herein. The sensor may beused for sensing an anatomical feature, which may be, for example, abranching point. In addition, the lumen-traveling device may include apower source 4130 such as a battery or microbattery, a fuel cell, a biofuel cell, an inductively driven power receiving structure driven by aremotely applied electromagnetic field, or an energy scavenging devicecapable of transducing blood flow, heart motion, gastrointestinal tractmotion, pulmonary motion, or muscle motion, for example. Alumen-traveling device may be sized to fit within various body lumens,in order to travel to a location in proximity to a stimulation target orsource of a biological signal of interest. For example, alumen-traveling device may be sized to fit within a blood vessel in thebrain in order to gain access to stimulation targets or signal source inregions of the brain, or sized to fit within a chamber of the heart fordelivering a cardiac pacing stimulus or recording electromagneticactivity from the heart.

In some embodiments the lumen-traveling device may include at least onestimulus source capable of generating a stimulus adapted for controllingor modifying heart activity. In other embodiments the lumen-travelingdevice may include at least one stimulus source capable of generating aneural stimulus.

Electromagnetic transducers may include electrodes for deliveringelectrical stimuli and/or sensing electrical or electrochemical signals,coils for generating or sensing magnetic fields, other magnetic fieldsensing devices such as Hall effect sensors, antennae for delivering orsensing electromagnetic fields, and other types of electromagneticdevices for delivering or sensing electromagnetic fields or energy,including but not limited to ion-sensitive capacitive or electroactivedevices, laser diodes, lasers, light emitting diodes, photodiodes, orphotodetectors. Some types of electromagnetic transducers may be usedfor both delivery of electromagnetic stimuli and sensing ofbioelectromagnetic signals, while other types of electromagnetictransducers may be suitable for stimulation or sensing, but not both.Various types of electrodes for delivering electrical stimuli and coilsfor delivering magnetic stimuli and associated signal generation andprocessing circuitry are known in the art. See for example, BUCHER,VOLKER; GRAF, MICHAEL; STELZLE, MARTIN; NISCH, WILFRIED; “Low-ImpedanceThin-Film Polycrystalline Silicon Microelectrodes for ExtracellularStimulation and Recording”; Biosensors and Bioelectronics; bearing adate of 1999; pp. 639-649; Vol. 14; Elsevier Science S.A.; located at:www.elsevier.com/locate/bios; CUI, XINYAN; HETKE, JAMILLE F.; WILER,JAMES A.; ANDERSON, DAVID J.; MARTIN, DAVID C.; “ElectrochemicalDeposition and Characterization of Conducting Polymer Polypyrrole/PPS onMultichannel Neural Probes”; Sensors and Actuators A Physical; bearing adate of 2001; pp. 8-18; Vol. 93; Elsevier Science B.V.; located at:www.elsevier.com/locate/sna; FIACCABRINO, G. C.; TANG, X.-M.; SKINNER,N.; DE ROOIJ, N. F.; KOUDELKA-HEP, M.; “Electrochemical Characterizationof Thin-Film Carbon Interdigitated Electrode Arrays”; Analytica ChimicaActa; bearing a date of 1996; pp. 155-160; Vol. 326; Elsevier ScienceB.V.; GITTER, ALFRED H.; FROMM, MICHAEL; SCHULZKE, JÖRG-DIETER;“Impedance Analysis for the Determination of Epithelial andSubepithelial Resistance in Intestinal Tissues”; Journal of Biochemicaland Biophysical Methods, bearing a date of 1998; pp. 35-46; Vol. 37;Elsevier Science B.V.; JANDERS, M.; EGERT, U.; STELZE, M.; NISCH, W.;“Novel Thin Film Titanium Nitride Micro-Electrodes with Excellent ChargeTransfer Capability for Cell Stimulation and Sensing Applications”; IEEEEngineering in Medicine and Biology Society; bearing a date of 1996; pp.245-247; IEEE; LOEB, G. E.; PECK, R. A.; MARTYNIUK, J.; “Toward theUltimate Metal Microelectrode”; Journal of Neuroscience Methods; bearinga date of 1995; pp. 175-183; Vol. 63; Elsevier Science B.V.; RIEDMÜLLER,J.; BOLZ, A.; REBLING, H.; SCHALDACH, M.; “Improvement of Stimulationand Sensing Performance of Bipolar Pacemaker Leads”; IEEE Eng. Med.Biol. Soc.; 1992; pp. 2364-2365; IEEE; ROUSCHE, PATRICK J.; PELLINEN,DAVID S.; PIVIN, DAVID P.; WILLIAMS, JUSTIN C.; VETTER, RIO J.; KIPKE,DARYL R.; “Flexible Polyimide-Based Intracortical Electrode Arrays withBioactive Capability”; IEEE Transactions on Biomedical Engineering;bearing a date March 2001; pp. 361-371; Vol. 48, No. 3; IEEE; RUTTEN,WIM; MOUVEROUX, JEAN-MARIE; BUITENWEG, JAN; HEIDA, CISKA; RUARDIJ, TEUN;MARANI, ENRICO; LAKKE, EGBERT; “Neuroelectronic Interfacing withCultured Multielectrode Arrays Toward a Cultured Probe”; Proceedings ofthe IEEE; bearing a date of July 2001; pp. 1013-1029; Vol. 89, No. 7;IEEE; ROBINSON, DAVID A.; “The Electrical Properties of MetalMicroelectrodes”; Proceedings of the IEEE; bearing a date of June 1968;pp. 1065-1071; Vol. 56, No. 6, all of which are incorporated herein byreference, for examples of electrodes for use in the central nervoussystem, peripheral nervous system, gut, or cardiac pacing.

Electrical circuitry and software/firmware for use in the acquisitionand processing of bioelectromagnetic signals are described in variousreferences, including the following examples which are incorporatedherein by reference: DILLIER, NORBERT; LAI, WAI KONG; ALMQVIST, BENGT;FROHNE, CAROLIN; MÜLLER-DEILE, JOACHIM; STECKER, MATTHIAS; VONWALLENBERG, ERNST; “Measurement of the Electrically Evoked CompoundAction Potential Via a Neural Response Telemetry System”; Annals OfOtology Rhinology and Laryngology; bearing a date of May 2002; pp.407-414; Vol. 111, No. 5; Annals Publishing Company; DONOGHUE, JOHN P.;“Review: Connecting Cortex to Machines: Recent Advances in BrainInterfaces”; Nature Neuroscience Supplement; bearing a date on November2002; pp. 1085-1088; Vol. 5; Nature Publishing Group; located at:http://www.nature.com/natureneuroscience; GOZANI, SHAI N.; MILLER, JOHNP.; “Optimal Discrimination and Classification of Neuronal ActionPotential Waveforms from Multiunit, Multichannel Recordings UsingSoftware-Based Linear Filters”; IEEE Transactions on BiomedicalEngineering; bearing a date of April 1994; pp. 358-372; Vol. 41, No. 4;IEEE; GRAY, CHARLES M.; MALDONADO, PEDRO E.; WILSON, MATHEW; MCNAUGHTON,BRUCE; “Tetrodes Markedly Improve the Reliability and Yield of MultipleSingle-Unit Isolation from Multi-Unit Recordings in Cat Striate Cortex”;Journal of Neuroscience Methods; bearing a date of 1995; pp. 43-54; Vol.63; Elsevier Science B.V.; HOFMANN, U. G.; FOLKERS, A.; MÖSCH, F.; HÖHL,D.; KINDLUNDH, M.; NORLIN, P.; “A 64(128)-Channel Multisite NeuronalRecording System”; bearing a date of 2002; pp. 1-4; JI, JIN; NAJAFI,KHALIL, WISE, KENSALL D.; “A Low-Noise Demultiplexing System for ActiveMultichannel Microelectrode Arrays”; IEEE Transactions of BiomedicalEngineering; bearing a date of January 1991; pp. 77-81; Vol. 38, No. 1;IEEE; OLSSON III, R. H.; GULARI, M. N.; WISE, K. D.; “Poster 114:Silicon Neural Recording Arrays with On-Chip Electronics for In-VivoData Acquisition”; Microtechnologies in Medicine and Biology; bearingdates of May 2, 2002-May 4, 2002; pp. 237-240; IEEE; and SCHOONHOVEN,R.; STEGEMAN, D. F.; “Models and Analysis of Compound Nerve ActionPotentials”; Critical Reviews in Biomedical Engineering; bearing a dateof 1991; pp. 47-111; Vol. 19, No. 1; CRC Press, Inc. An example ofelectronic circuitry for control of stimulation with an implantedelectrode system is provided, for example, in LOEB, GERALD E.; PECK,RAYMOND A.; MOORE, WILLIAM H.; HOOD, KEVIN; “BION System for DistributedNeural Prosthetic Interfaces”; Medical Engineering and Physics; bearinga date of 2001; pp. 9-18; Vol. 23; Elsevier Science Ltd.; located at:www.elsevier.com/locate/medengphy which is incorporated herein byreference.

Various references discuss the theoretical basis for electromagneticsensing and stimulation. Examples (all of which are included herein byreference) include: HODGKIN, A. L.; HUXLEY, A. F.; “A QuantitativeDescription of Membrane Current and its Application to Conduction andExcitation in Nerve”; Journal of Physiology; bearing a date of 1952; pp.500-544; Vol. 117; MARKS, WILLIAM B.; LOEB, GERALD E.; “Action Currents,Internodal Potentials, and Extracellular Records of Myelinated MammalianNerve Fibers Derived from Node Potentials”; Biophysical Journal; 1976;pp. 655-668; Vol. 16; MCNEAL, DONALD R.; “Analysis of a Model forExcitation of Myelinated Nerve”; IEEE Transactions on BiomedicalEngineering; bearing a date of July 1976; pp. 329-337; Vol. BME-23, No.4; RATTAY, FRANK; “Analysis of Models for Extracellular FiberStimulation”; IEEE Transactions on Biomedical Engineering; bearing adate of July 1989; pp. 676-682; Vol. 36, No. 7; IEEE; RATTAY, FRANK,ABERHAM, MATTHIAS; “Modeling Axon Membranes from Functional ElectricalStimulation”; IEEE Transactions on Biomedical Engineering; bearing adate of December 1993; pp. 1201-1209; Vol. 40, No. 12; IEEE; andSTRUIJK, JOHANNES JAN; “The Extracellular Potential of a MyelinatedNerve Fiber in an Unbounded Medium and in Nerve Cuff Models”;Biophysical Journal; bearing a date of June 1997; pp. 2457-2469; Vol.72; Biophysical Society. Related methods and devices, as well asunderlying theory, are also described in various texts, for example, K.W. Horch and G. S. Dhillon, Editors, Neuroprosthetics: Theory andPractice (Series on Bioengineering and Biomedical Engineering—Vol. 2),World Scientific Publishing Co. Pte. Ltd, Singapore, 2004, and J.Malmivuo and R. Plonsey, Bioelectromagnetism: Principles andApplications of Bioelectric and Biomagnetic Fields, Oxford UniversityPress, NY, 1995, http://butler.cc.tut.fi/˜malmivuo/bem/bembook/, whichis incorporated herein by reference. As used herein, the term “coil”refers to various structures used to generate magnetic fields for use inmagnetic stimulation. In some embodiments, a coil may include multiplecurrent-carrying loops and in other embodiments a coil may include asingle full or partial loop; while coils may often include generallyrounded or circular loops (full or partial) coils are not limited to anyparticular configuration of loops. Optical stimulation may be performedby methods as described in U.S. Pat. No. 6,921,413, which isincorporated herein by reference.

In various embodiments, the stimulus source may be capable of generatinga depolarizing stimulus sufficient to produce depolarization of at leasta portion of the target tissue, or a hyperpolarizing stimulus sufficientto produce hyperpolarization of at least a portion of the target tissue.In some embodiments, the stimulus source may be capable of generating astimulus sufficient to produce functional inhibition of activity of thetarget tissue, while in other embodiments the stimulus source may becapable of generating a stimulus sufficient to produce functionalpromotion of activity of the target tissue. Stimuli sufficient toproduce functional inhibition or promotion of activity in a targettissue or portion thereof may be determined experimentally or selectedbased upon information and knowledge available to a person of skill inthe art. In some embodiments, the stimulus source may be capable ofgenerating a pre-programmed stimulation pattern. In some embodiments,the stimulus source may be capable of generating a stimulus in responseto the sense signal from a sensor, which may be an electrical sensor, amagnetic sensor, or a chemical sensor.

The at least one stimulus source may be capable of generating a stimulusin response to the signal from the remote portion.

The lumen-traveling device of may include at least one signal processingportion capable of processing the output signal from the electromagnetictransducer, for example by amplifying the output signal recorded fromthe target tissue with the at least one electromagnetic transducer. Thesignal processing portion may process the output signal by varioussignal processing methods, including, for example, filtering orperforming feature detection/pattern recognition on the output signal.

As illustrated in FIG. 57, in some embodiments, the lumen-travelingdevice may include at least one signal processing portion capable ofprocessing the output signal from the electromagnetic transducer; and atleast one transmitter configured to transmit an output of the at leastone signal processing portion to a remote location. Alternatively, or inaddition, a transmitter may be configure to transmit informationrelating to the status, location, or position of the lumen-travelingdevice or relating to an action taken by the lumen-traveling device(e.g., delivery of an electromagnetic stimulus to a target tissue) to aremote location.

Or, referring back to FIG. 55, the lumen-traveling device may include atleast one signal processing portion capable of processing the outputsignal from the electromagnetic transducer; and at least one datastorage location configured for storing an output of the at least onesignal processing portion of the lumen-traveling device.

FIG. 58 shows a method of emplacing an electromagnetic stimulationdevice. The method includes the steps of causing a self-propellingelectromagnetic stimulation device to travel within a body tube tree ofa subject toward a target site (step 4152); if a branch point includingtwo or more branches within the body tube tree is reached by theself-propelling electromagnetic stimulation device, causing theself-propelling electromagnetic stimulation device to enter a selectedbranch (step 4154); and causing the self-propelling electromagneticstimulation device to stop traveling upon reaching the target site (step4156).

As used herein, the term “self-propelling” refers to a device having anon-board propelling mechanism for generating a propulsion force. Thepower source for the propelling mechanism may be located on-board thedevice, or, in some embodiments, power may be beamed or transmitted tothe device from an external source. Control circuitry for controllingoperation of the propelling mechanism may be on-board the device, or, insome embodiments, located at least in part in a remote portion. Forexample, causing a self-propelling electromagnetic stimulation device totravel within a body tube tree is considered to include causing thegeneration of control or driving signal with electronic circuitryon-board or at least in part off-board the device, but is not consideredto include the application of an external force to cause movement of theelectromagnetic stimulation device.

FIG. 59 illustrates possible expansions of the method shown in FIG. 58,in which the method may include a step of introducing theself-propelling electromagnetic stimulation device into the body tubetree at 4202; causing a self-propelling electromagnetic stimulationdevice to travel within a body tube tree of a subject toward a targetsite (step 4204); if a branch point including two or more brancheswithin the body tube tree is reached by the self-propellingelectromagnetic stimulation device, causing the self-propellingelectromagnetic stimulation device to enter a selected branch (step4206); and causing the self-propelling electromagnetic stimulationdevice to stop traveling upon reaching the target site (step 4208). Themethod may also include causing the self-propelling electromagneticstimulation device to engage the wall of the body tube tree at thetarget site, as shown at step 4210. The body tube tree into which theself-propelling electromagnetic stimulation device is introduced may bethe cardiovascular system of the subject, as indicated at 4212, therespiratory system of the subject, as indicated at 4214, or CSF-space ofthe subject, as indicated at 4216. The branch which the self-propellingelectromagnetic stimulation device enters at step 4206 may be selectedbecause it is expected to lead toward the target site, as indicated at4220; or the branch may be selected on some other basis (e.g., size,orientation, direction of fluid flow through the branch, etc.).

FIG. 60 shows a method of emplacing a self-propelling electromagneticstimulation device generally as shown in FIG. 58, which includes causinga self-propelling electromagnetic stimulation device to travel within abody tube tree of a subject toward a target site (step 4252); if abranch point including two or more branches within the body tube tree isreached by the self-propelling electromagnetic stimulation device,causing the self-propelling electromagnetic stimulation device to entera selected branch (step 4254); and causing the self-propellingelectromagnetic stimulation device to stop traveling upon reaching thetarget site (step 4256). As indicated in dashed box 4260, the method mayinclude causing the self-propelling electromagnetic stimulation deviceto travel within the body tube tree toward a target site located withina chamber of the heart of the subject. Alternatively, as shown in dashedbox 4262, the method may include causing the self-propellingelectromagnetic stimulation device to travel within the body tube treetoward a target site located within the vasculature of the brain of thesubject. Here and elsewhere, dashed boxes are used to indicate optionaland/or alternative steps in a flow diagram. The target site may belocated within the vasculature of the brain in the vicinity of astimulation target including tissue responsive to electromagneticstimulation—examples of which include the hypothalamus (as indicated at4264), cingulate cortex (as indicated at 4266), fornix (as indicated at4268), anterior thalamus (as indicated at 4270), subthalamic nucleus (asindicated at 4272), globus pallidus interna (as indicated at 4274),insula (as indicated at 4276), or deep brain (as indicated at 4278).

A large number of brain areas may be suitable sites for stimulation,including but not limited to the myelencephalon or hindbrain, includingthe medulla oblongata (medullary pyramids, or nuclei including arcuatenucleaus of medulla, solitary nucleus, hypoglossal nucleus, nucleusambiguus, olivary body, inferior olivary nucleus, cuneate nucleus,accessory cuneate neucleus, gracile nucleus, inferior salivatorynucleus, raphe nuclei [obscurus, magnus, and pallidus], area postrema,posterior nucleus of vagus nerve); the metencephalon, including the pons(pontine tegmentum, superior salivary nucleus, trapezoid body, pontinenuclei [superior olivary nucleus, trigeminal nerve nuclei, abducensnucleus, facial motor nucleus, cochlear nuclei vestibular nuclei], locusceruleus, paramedian pontine reticular formation, nucleus centralissuperior) and the cerebellum (cerebellar vermis, cerebellar hemispheres[anterior lobe, posterior lobe, flocculonodular lobe], cerebellarnuclei, fastigial nucleus, globose nucleus, emboliform nucleus, dentatenucleus); the mesencephalon or midbrain, including the tectum (inferiorcolliculi and superior colliculi), the cerebral peduncle, the midbraintegmentum (ventral tegmental area, Red Nucleus, substantia nigra, andcrus cerebri), and the pretectum; the diencephalon, includingepithalamus (pineal body, habenular nuclei stria medullares, and teniathalami), the thalamus including the anterior nuclear group(anteroventral nucleus, anterodorsal nucleus, anteromedial nucleus),medial nuclear group (dorsomedial nucleus, midline nuclear group,paratenial nucleus, paraventricular nucleus, reniens nucleus, rhomboidalnucleus), intralaminar nuclear group (centromedial nucleus,parafascicular nucleus, paracentral nucleus, central lateral nucleus,central medial nucleus), lateral nuclear group (lateral dorsal nucleus,lateral posterior nucleus, pulvinar), ventral nuclear group (ventralanterior nucleus, ventral lateral nucleus, ventral posterior nucleus),metathalamus (medial geniculate body, lateral geniculate body) andthalamic reticular nucleus, the hypothalamus (optic chiasm, arcuatenucleus, subformical organ, preoptic area, suprachiasmatic nucleus,supraoptic nucleus, periventricular nucleus, paraventricular nucleus,ventromedial nucleus, dorsomedial nucleus, lateral hypothalamus,infundibulum, tuber cinereum, tuberal region, mammillary bodies,mammillary nucleus), the subthalamus (thalamic nucleus, zona incerta),and the pituitary gland (neurohypophysis, intermediate pituitary,adenohypophysis); the Telencephalon or cerebrum including the cerebralhemispheres, which include the white matter (corona radiata, internalcapsule, external capsule, extreme capsule, arcuate fasciculus, uncinatefasciculus), subcortical structures (amygdala, including centralnucleus, medial nucleus, cortical and basomedial nuclei, and lateral andbasolateral nuclei hippocampus, including dentate gyrus and cornuammonis; and basal ganglia including striatum, nucleus lentiformis,globus pallidus, medial pallidum (GPi), lateral pallidum (GPe), putamen,nucleus caudatus, claustrum, corpus amygdaloideum), Rhinencephalon(olfactory bulb, piriform cortex, anterior olfactory nucleus, olfactorytract, anterior commissure), cerebral cortex (frontal lobe includingprimary motor cortex and Brodmann area 4, prefrontal cortex,supplementary motor cortex, premotor cortex) and Brodmann areas 6, 8, 9,10, 11, 24, 25, 32, 33, 44, 45, 46, 47), temporal lobe including primaryauditory cortex-A1, A2, inferior temporal cortex, posterior inferiortemporal cortex, and Brodmann areas 9, 20, 21, 22, 27, 34, 35, 36, 37,38, 41, 42), parietal lobe including primary somatosensory cortex-S1,S2, posterior parietal cortex, precuneus, Brodmann areas 1, 2, 3, 5, 7,23, 26, 29, 31, 39, 40, occipital lobe including primary visual cortex(V1), V2, cuneus and Brodmann areas 17, 18, and 19, insula, cingulatecortex (anterior cingulate, posterior cingulate, Brodmann areas 23, 24,26, 29, 30, 31 and 32); and the limbic system, including the amygdala,cingulate gyrus, fornicate gyrus, hippocampus, hypothalamus, mammillarybody, nucleus accumbens, orbitofrontal cortex, and parahippocampalgyrus. In addition to brain structures, other portions of the nervoussystem, both central (e.g. spinal canal, retina, brain, etc.) andperipheral may be responsive to electrical, magnetic and/or other formsof stimulation. In addition, central and peripheral portion of thenervous system may also be sources of bioelectric activity that may bedetected with a lumen-traveling biological interface device. Othertissues (including smooth, skeletal, and cardiac muscles) may also besources of bioelectric/biomagnetic signals and may also be responsive toelectrical, magnetic, chemical or other stimuli.

FIG. 61, shows a method of emplacing a self-propelling electromagneticstimulation device that is an expansion of the method shown in FIG. 58,and includes selecting a target site in proximity to a stimulationtarget, the stimulation target including tissue responsive toelectromagnetic stimulation (at 4302); causing a self-propellingelectromagnetic stimulation device to travel within a body tube tree ofa subject toward a target site (step 4304); if a branch point includingtwo or more branches within the body tube tree is reached by theself-propelling electromagnetic stimulation device, causing theself-propelling electromagnetic stimulation device to enter a selectedbranch (step 4306); and causing the self-propelling electromagneticstimulation device to stop traveling upon reaching the target site (step4308). For example the stimulation target may be the cingulate cortex,as indicated at 4312, the hypothalamus, as indicated at 4314, thefornix, as indicated at 4316, the anterior thalamus, as indicated at4318, the subthalamic nucleus as indicated at 4320, the globus pallidusinterna, as indicated at 4322, the insula, as indicated at 4324, or thedeep brain, as indicated at 4326.

Activity in certain brain regions is associated with certain moods,feelings, sensations, or behaviors, and stimulation in these brain areas(which may be excitatory/promoting or inhibitory) may be used to up- ordown-regulate these moods or behaviors. For example, stimulation of thehypothalamus is thought to produce a sensation of satiety, which mayreduce overeating leading to obesity (see for example U.S. Pat. No.5,782,798; also see U.S. Pat. No. 6,950,707 relating to stimulation totreat obesity, which are incorporated herein by reference; stimulationof the cingulate cortex or vagus nerve may reduce depression; injury tothe insula may diminish addictive behaviors such as smoking, suggestingthat stimulation in this area could influence addictive behaviors (seeN. H. Naqvi et al., “Damage to the Insula Disrupts Addiction toCigarette Smoking,” Science Vol. 315, pp. 531-534, 2007,doi:10.1126/science.1135926, incorporated herein by reference);stimulation of the fornix and anterior thalamus (thalamic nucleus) maybe used in the treatment of epilepsy (see U.S. Pat. Nos. 7,003,352;6,597,954; 6,134,474; and 6,337,997 regarding stimulation of variousbrain areas to treat epilepsy, all of which are incorporated herein byreference), stimulation of the subthalamic nucleus may reduceParkinson's, and stimulation of the globus pallidus interna may suppresstremor. Stimulation of various areas may reduce schizophrenia or bipolardisorder. A number of patents, all of which are incorporated herein byreference, describe methods of electrically, magnetically and/orchemically stimulating various tissues to treat various problems,including stimulating various brain areas to treat neurologicaldisorders (U.S. Pat. Nos. 6,128,538 and 6,016,449) or sleep disorders(U.S. Pat. No. 5,335,657); stimulating vagus nerve to treat dementia(U.S. Pat. No. 5,269,303); stimulating deep brain or other areas totreat pain and/or headaches (U.S. Pat. Nos. 7,013,177; 6,735,475; and6,402,678); stimulating deep brain to treat Parkinsons disease (U.S.Pat. No. 6,920,359); stimulating deep brain or motor cortex to suppressessential tremor (U.S. Pat. No. 6,959,215); and stimulating stomachand/or small intestine to treat gastrointestinal disorders (U.S. Pat.No. 6,591,137).

Many stimulation/recording targets may be accessed via one or more bodylumens. For example, the hippocampus may be accessed via the temporalhorn of the lateral ventricles. Deep brain structures (e.g. thehypothalamus) may be accessed via the third ventricle, or via variousblood vessels. Basal ganglia may be accessed via the lenticulostriateartery or thalamostriate vessels. Regions of the heart may be accessedthrough the chambers of the heart. Selection of suitable body lumens foruse as target sites for providing access to a stimulation/recordingtarget may be based upon anatomical considerations. One considerationmay be proximity of the body lumen (or a region thereof) to thestimulation/recording target. Proximity may be determined simply on thebasis of physical distance, or may take into account tissue propertiesthat influence the transmission of stimuli/signals between the targetsite and the stimulation/recording target (e.g., electrical conductivityor capacitance, magnetic permittivity or permeability, etc.). Anotherconsideration may be the ability to position the lumen-traveling devicein the body lumen without producing unwanted effects; for example, itmay be undesirable to block the supply of blood or other fluid to atissue region or to prevent drainage of a fluid (blood, CSF, etc.) froma tissue region, so a body lumen that is small enough that the presenceof a lumen-traveling device would significantly diminish fluid movementin the body lumen may be a less desirable target site, as might be abody lumen that is the single source/drainage for a tissue region.Conversely, a body lumen that is large relative to the lumen-travelingdevice, or that is one of multiple body lumens supplying or draining atissue region may be a more desirable target site.

As shown in FIG. 62, a method of emplacing an self-propellingelectromagnetic stimulation device may include selecting a target sitebased upon anatomical information as indicated at step 4352 (e.g.,position within a particular blood vessel or cerebral ventricle known tobe close to a particular brain structure may be detected by imaging) orselecting a target site based upon measurement of a physiologicalparameter, as indicated at step 4354. The physiological parameter mayinclude a signal characteristic of a selected region of the nervoussystem (as shown at 4368) or a signal characteristic of a selectedregion of the heart (as shown at 4370), or the physiological parametermay include a signal-to-noise ratio indicative of good signaltransduction path between the self-propelling electromagneticstimulation device and the stimulation target (as shown at 4372).

As indicated at step 4356, the method may include selecting aself-propelling electromagnetic stimulation device sized to fit withinthe target site, for example by selecting the self-propellingelectromagnetic stimulation device from an assortment of self-propellingelectromagnetic stimulation devices of different sizes as indicated atstep 4374. Alternatively, in some cases, as indicated step 4358, thesize of the self-propelling electromagnetic stimulation device may beadjusted to fit within the target site. Further steps of causing aself-propelling electromagnetic stimulation device to travel within thebody tube tree of a subject toward a target site, at step 4360; if abranch point including two or more branches within the body tube tree isreached by the self-propelling electromagnetic stimulation device,causing the stimulation device to enter a selected branch (step 4362);and causing the self-propelling electromagnetic stimulation device tostop traveling upon reaching the target site (step 4364) are asdescribed elsewhere herein.

FIG. 63 depicts a further variant of the basic method depicted in FIG.58, showing several additional possible steps. For example, the methodmay include the step of introducing the self-propelling electromagneticstimulation device into the body tube tree by injection, as shown at4502, or, alternatively, releasing the self-propelling electromagneticstimulation device from a catheter introduced into the body tube tree ofthe subject, as shown at 4504.

As shown at step 4506, the method may include causing theself-propelling electromagnetic stimulation device to travel within thebody tube tree of a subject toward a target site, which may be performedunder the control of a remote portion, as shown at 4508, oralternatively, under the control of a control system located at least inpart on the self-propelling electromagnetic stimulation device, as shownat 4510. As shown at 4512, if a branch point including two or morebranches within the body tube tree is reached by the self-propellingelectromagnetic stimulation device, the method may include causing theself-propelling electromagnetic stimulation device to enter a selectedbranch. For example, the method may include detecting the branch pointwith a sensor on the self-propelling electromagnetic stimulation device,as indicated at 4514. As shown in previous figures, the method mayinclude causing the self-propelling electromagnetic stimulation deviceto stop traveling upon reaching the target site, as shown at 4516. Themethod may include engaging a wall of the body tube tree by severalpossible alternative methods: the method may include engaging a wall ofthe body tube tree by causing at least a portion of the self-propellingelectromagnetic stimulation device to expand to form a pressure fit withthe wall of the body tube tree (step 4518), by releasing an adhesivematerial from the self-propelling electromagnetic stimulation device(step 4520), or extending at least one claw or barb-like structure fromthe self-propelling electromagnetic stimulation device to penetratinglyengage the wall of the body tube tree (step 4522).

FIG. 64 illustrates the introduction of a self-propellingelectromagnetic stimulation device 4550 into the body 4552 of a subjectby injection. In the example depicted in FIG. 64, the self-propellingelectromagnetic stimulation device 4550 is a cardiac stimulation device(e.g. a portion of a pacemaker). Self-propelling electromagneticstimulation device 4550 is injected into arm vein 4554 (e.g. thecephalic vein) with hypodermic needle 4556, and travels in the directionof the blood flow to right atrium 4558 of heart 4560, along the routeindicated by the dashed arrow. From right atrium 4558, theself-propelling electromagnetic stimulation device travels may travel tothe base of right ventricle 4562, where it may reside and delivercardiac pacing stimuli.

FIG. 65 illustrates the introduction of a lumen-traveling biologicalinterface device 4600 (e.g. a neural stimulation and/or sensing device)into the brain 4602 of a subject 4604 with a catheter 4606. Catheter4606, carrying lumen-traveling biological interface device (the positionof the lumen-traveling biological interface device on the catheter isindicated by an open circle 4608), is introduced into a vein (e.g.femoral 4610 as depicted in FIG. 65, or alternatively an arm vein asshown in FIG. 64). Catheter 4606 is advanced into the right atrium 4612of the heart 4614, through heart 4614, and out via aorta 4616, and intocarotid artery 4618. Lumen-traveling biological interface device 4600may then be released from catheter 4606 and may travel through the brainvasculature (e.g. on the route indicated by the dashed line) until itreaches a target site within the brain. Catheter and deviceconfiguration may be modified in some embodiments to carry more than onedevice on the catheter in order to accomplish delivery of two or moredevices at one time with a catheter.

FIG. 66 illustrates the introduction of lumen-traveling stimulationdevices to muscle. In FIG. 66, lumen-traveling devices 5150, 5152, 5154,and 5156 are injected into vein 5158 of arm 5160 of a subject withsyringe 5162, for example, where, as indicated by the dashed arrows,they may travel toward the muscle 5164 drained by the vein 5158, againstthe flow of blood, into capillaries 5170, 5172, 5174, and 5176 in muscle5164, where they will reside in order to perform electromagneticstimulation of the muscle 5164, e.g. for performing functionalelectromagnetic stimulation. In FIG. 66, lumen-traveling devices are notdrawn to scale, but are indicated by black circles for purposed ofillustration. Stimulation parameters suitable for use in stimulation ofmuscle with multiple, distributed, implanted microelectrodes aredescribed in LOEB, GERALD E.; PECK, RAYMOND A.; MOORE, WILLIAM H.; HOOD,KEVIN; “BION System for Distributed Neural Prosthetic Interfaces”;Medical Engineering and Physics; bearing a date of 2001; pp. 9-18; Vol.23; Elsevier Science Ltd.; located at:www.elsevier.com/locate/medengphy, which is incorporated herein byreference.

FIGS. 67A and 67B show further variations of the method shown in FIG.58. The method may include selecting a target site in proximity to astimulation target, the stimulation target including tissue responsiveto electromagnetic stimulation, in step 4702. In some embodiments, themethod may also include adjusting the size of the self-propellingelectromagnetic stimulation device to fit within the target site, asshown at step 4704. As shown in FIG. 58, the method may include causinga self-propelling electromagnetic stimulation device to travel within abody tube tree of a subject toward a target site at 4706, and, at step4708, if a branch point including two or more branches within the bodytube tree is reached by the self-propelling electromagnetic stimulationdevice, causing the self-propelling electromagnetic stimulation deviceto enter a selected branch. At step 4710, the method includes the stepof causing the self-propelling electromagnetic stimulation device tostop traveling upon reaching the target site. At step 4712, the methodincludes delivering an electromagnetic stimulus to the stimulationtarget with the self-propelling electromagnetic stimulation device.Various types of stimuli may be applied as shown in 4712 in FIG. 67A andin 4714, 4716, 4418, 4720, 4722, 4724, 4726, and 4728 in FIG. 67B (whichis a continuation of FIG. 67A at connection points A and B). Forexample, the electromagnetic stimulus may include one or more of adepolarizing electromagnetic stimulus, as shown at 4714, ahyperpolarizing electromagnetic stimulus as shown at 4716, or apulsatile electromagnetic stimulus, as shown at 4718. In someembodiments, the electromagnetic stimulus may be a functionallyinhibiting stimulus (i.e., a stimulus sufficient to produce functionalinhibition of activity of the target tissue or a portion thereof) asindicated at 4727 or a functionally promoting stimulus (i.e., a stimulussufficient to produce functional promotion of activity of target tissueor a portion thereof), as indicated at 4729 in FIG. 67B. Various typesof electrical and magnetic stimuli are well known to those of skill inthe art, as exemplified by P. H. Peckham and J. S. Knutson, “FunctionalElectrical Stimulation for Neuromuscular Applications,” Annu. Rev.Biomed. Eng., Vol. 7, 2005, pp. 327-60, Published online Mar. 23, 2005;doi:10.1146/annurev.bioeng.6.040803.140103, copyright 2005; KOBETIC,RUDI; TRIOLO, RONALD J.; UHLIR, JAMES P.; BIERI, CAROLE; WIBOWO,MICHAEL; POLANDO, GORDIE; MARSOLAIS, E. BYRON; DAVIS JR., JOHN A.;FERGUSON, KATHLEEN A.; SHARMA, MUKUT; “Implanted Functional ElectricalStimulation System for Mobility in Paraplegia: A Follow-Up Case Report”;IEEE Transactions on Rehabilitation Engineering; bearing a date ofDecember 1999; pp. 390-398; Vol. 7, No. 4; IEEE; INMANN, ANDREAS;HAUGLAND, MORTEN; HAASE, JENS; BIERING-SØRENSEN, FIN; SINKJAER, THOMAS;“NeuroReport: Signals from Skin Mechanoreceptors used in Control of aHand Grasp Neuroprosthesis”; Motor Systems; bearing a date of Sep. 17,2001; pp. 2817-2819; Vol. 12, No. 13; Lippincott Williams & Wilkins; C.R. Butson and C. C. McIntyre, “Role of electrode design on the volume oftissue activated during deep brain stimulation,” J. Neural Eng., Vol. 3,2006, pp. 1-8, Published Online 19 Dec. 2005,doi:10.1088/1741-2560/3/1/001; and FANG, ZI-PING; MORTIMER, J. THOMAS;“Selective Activation of Small Motor Axons by Quasitrapezoidal CurrentPulses”; IEEE Transactions on Biomedical Engineering; bearing a date ofFebruary 1991; pp. 168-174; Vol. 38, No. 2; IEEE; which are incorporatedherein by reference.

In some embodiments, as shown at step 4720, the method may includedetecting a bioelectric signal from the stimulation target or at leastone region associated therewith and delivering an electromagneticstimulus responsive to detecting the bioelectric signal from thestimulation target or the at least one region associated therewith.Alternatively, in some embodiments, as shown at step 4722, the methodmay include detecting a biomagnetic signal from the stimulation targetor at least one region associated therewith and delivering anelectromagnetic stimulus responsive to detecting the biomagnetic signalfrom the stimulation target or the at least one region associatedtherewith. In some embodiments, as shown at step 4724, the method mayinclude detecting a biochemical signal from the stimulation target or atleast one region associated therewith and delivering an electromagneticstimulus responsive to detecting the biochemical signal from thestimulation target or the at least one region associated therewith.Biochemical signals may be detected using various sensors as describedherein, including biosensors of various types, immunosensors, pHsensors, etc. In still other embodiments, as shown at step 4721, themethod may include detecting a biophysical signal from the stimulationtarget or at least one region associated therewith and delivering anelectromagnetic stimulus responsive to detecting the biophysical signalfrom the stimulation target or the at least one region associatedtherewith. A biophysical signal may include, for example, a pressure orflow condition, e.g. a pressure or flow signal associated with blood inthe heart or other portion of the circulatory system. Delivery of anelectromagnetic stimulus to the stimulation target may be performed witha single electromagnetic transducer, as indicated in 4723, or withmultiple electromagnetic transducers 4725.

In various embodiments, stimuli delivered in response to a detectedsignal may be used to amplify naturally occurring activity, or toproduce an effect that is complementary to naturally occurring activity.Alternatively, stimuli delivered in response to a detected signal may beused to diminish or damp naturally occurring activity, or produce aneffect that counters naturally occurring activity. In some embodiments,sensed activity may be used to indicate proximity to a stimulationtarget. In some embodiments, stimulation may be correlated temporally,but not spatially, with the detected signal. The method may also includedelivering an electromagnetic stimulus to the stimulation target inresponse to a remote control signal, as indicated at 4726, or inresponse to a pre-programmed stimulation pattern, as indicated at 4728.

Methods of detecting and analyzing bioelectric and/or biomagneticsignals are well known to those of skill in the art, as exemplified byK. W. Horch and G. S. Dhillon, Editors, Neuroprosthetics: Theory andPractice (Series on Bioengineering and Biomedical Engineering—Vol. 2),World Scientific Publishing Co. Pte. Ltd, Singapore, 2004, inparticular, chapters 2.2, 2.4, 4.3 and 5.2, and J. Malmivuo and R.Plonsey, Bioelectromagnetism: Principles and Applications of Bioelectricand Biomagnetic Fields, Oxford University Press, NY, 1995,http://butler.cc.tut.fi/˜malmivuo/bem/bembook/, which are incorporatedherein by reference.

FIG. 68 depicts an example of detection of a bioelectric signal anddelivery of a stimulation in response to the detected signal isillustrated in FIG. 68. A heart 4750 of a subject is depicted in FIG.68. A lumen-traveling device 4752 located in right atrium 4754 may sensenaturally occurring bioelectrical activity generated by the sinoatrial4756 node of heart 4750, for example, indicating the need to initiate aheartbeat. In the case of a conduction block between sinoatrial node4756 and atrioventricular node 4758, the signal will not be transmittednormally and contraction of the ventricles 4760 and 4762 will not beinitiated properly. In order to compensate for this defect,lumen-traveling device 4752 may transmit a signal to secondlumen-traveling stimulation device 4764 located in right ventricle 4760,which may then deliver an electrical pacing signal to cause contractionof ventricles 4760 and 4762.

FIG. 69 is a flow diagram of a further variation of the method shown inFIG. 58. The method of FIG. 69 includes causing a self-propellingelectromagnetic stimulation device to travel within a body tube tree ofa subject toward a target site at step 4772, if a branch point includingtwo or more branches within the body tube tree is reached by theself-propelling electromagnetic stimulation device, causing theself-propelling electromagnetic stimulation device to enter a selectedbranch at step 4774, and causing the self-propelling electromagneticstimulation device to stop traveling upon reaching the target site at4776 as shown in previously described embodiments. Additional steps mayinclude storing a record of the operation of the self-propellingelectromagnetic stimulation device as indicated at 4778 and/ortransmitting a representation of an activity of the self-propellingelectromagnetic stimulation device to a remote portion as indicated at4780. The method may also include causing the self-propellingelectromagnetic stimulation device to resume traveling, as indicated at4782. Although the steps of storing a record of the operation of theself-propelling electromagnetic stimulation device and transmitting arepresentation of an activity of the self-propelling electromagneticstimulation device are presented in a particular order in the flowdiagram of FIG. 69, in practice these steps may be performed at varioustimes during the operation of the device, and in some cases may beperformed prior to the device stopping traveling or after the deviceresumes traveling (or independent of starting or stopping of the device,in that the device may not necessarily stop or start, but may insteadmove continuously).

FIG. 70 is a flow diagram of a method of emplacing an self-propellingelectromagnetic stimulation device as shown in FIG. 58, including thesteps of causing a self-propelling electromagnetic stimulation device totravel within a body tube tree of a subject toward a target site (step4802); if a branch point including two or more branches within the bodytube tree is reached by the self-propelling electromagnetic stimulationdevice, causing the self-propelling electromagnetic stimulation deviceto enter a selected branch (step 4804); and causing the self-propellingelectromagnetic stimulation device to stop traveling upon reaching thetarget site (step 4806). At 4808, the method further includes emplacingat least one additional self-propelling electromagnetic stimulationdevice by causing the at least one additional self-propellingelectromagnetic stimulation device to travel within the body tube treeof the subject toward an additional target site; wherein if a branchpoint including two or more branches within the body tube tree isreached by the at least one additional self-propelling electromagneticstimulation device, causing the at least one self-propellingelectromagnetic stimulation device to enter a selected branch; andcausing the at least one self-propelling electromagnetic stimulationdevice to stop traveling upon reaching the additional target site.

FIG. 71 is a flow diagram of a further extension of the method of FIG.58, which includes the steps of causing a self-propellingelectromagnetic stimulation device to travel within a body tube tree ofa subject toward a target site at 4822, and if a branch point includingtwo or more branches within the body tube tree is reached by theself-propelling electromagnetic stimulation device, causing theself-propelling electromagnetic stimulation device to enter a selectedbranch at step 4824. In some embodiments may include the variantsspecified in steps 4826 and 4828. As indicated in 4826, the method mayinclude pulling one or more electromagnetic stimulation devices towardthe target site with the self-propelling electromagnetic stimulationdevice. Alternatively, or in addition, the method may include pushingone or more electromagnetic stimulation devices toward the target sitewith the self-propelling electromagnetic stimulation device, asindicated at 4828. And, as shown in previous figures, the method mayinclude causing the self-propelling electromagnetic stimulation deviceto stop traveling upon reaching the target site, as indicated at 4830.

The use of multiple stimulation devices is depicted in FIG. 72. FIG. 72illustrates brain 4850 of a subject, including lateral ventricals 4852and 4854, third ventricle 4856, and thalamus 4858 (indicated generallyas the striped region in FIG. 72). Stimulation devices 4860, 4862, 4864,and 4866 are positioned in lateral ventricle 4852, stimulation devices4868 and 4870 are positioned in third ventricle 4856. The stimulationdevices are thus distributed around thalamus 4858 and may be used toselectively stimulate thalamus 4858 (or portions thereof). For example,relatively low stimuli delivered through multiple stimulation devicesmay overlap to activate restricted regions of the thalamus. In anotherexample, by activating multiple stimulation devices in appropriatelyselected patterns, spatially and/or temporally complex stimulationpatterns may be produced. Stimulation devices 4860, 4862, 4864, and 4866are linked by tethers 4872, 4874, and 4876, which may be formed ofsuture material, wire, cable, or fiber, for example. By forming a linkedgroup of stimulation devices, the relative spacing between thestimulation devices may be controlled, and positioning of thestimulation devices relative to anatomical structures may befacilitated. A linked group of stimulation devices may be used in thepractice of the method steps 4826 and 4828 of FIG. 71; a relativelyflexible tether may be used if electromagnetic stimulation devices areto be pulled by a self-propelling electromagnetic stimulation device,while a more rigid linkage may be used if electromagnetic stimulationdevices are to be pushed by a self-propelling electromagneticstimulation device

In some embodiments, a method may include using a lumen-traveling deviceto carry a bioelectromagnetic interface device to a target site. Thisapproach is illustrated in FIG. 73A-73C. In FIG. 73A, bioelectromagneticinterface device 4950 is carried through body tube tree 4952 byself-propelling lumen-traveling device 4954, which may be of the typedepicted generally in FIGS. 24 and 25A-25B. For example, self-propellinglumen-traveling device 4954 may include grasper 4956 for carryingbioelectromagnetic interface device 4950. Self-propellinglumen-traveling device 4954 may include sensor 4958, which is configuredto detect the arrival of the bioelectromagnetic interface device at thetarget site 4960, near stimulation target 4962. Sensor 4958 may be anyof various types of sensors, as described herein. In FIG. 73A, theself-propelling lumen-traveling device 4954, carrying bioelectromagneticinterface device 4950, travels through body tube tree 4952 in thedirection indicated by the arrow. In FIG. 73B, the arrival ofbioelectromagnetic interface device 4950 at target site 4960 is detectedby sensor 4958. Bioelectromagnetic interface device 4950 may then bereleased from self-propelling lumen-traveling device 4954, andself-propelling lumen-traveling device may move away from target site4960, leaving the bioelectromagnetic interface device at target site4960.

FIG. 74 is a flow diagram of a method of configuring abioelectromagnetic interface system, including moving a at least onebioelectromagnetic interface device through a body tube tree of asubject toward a target site with a self-propelling lumen-travelingdevice (at step 4902); detecting the arrival of the at least onebioelectromagnetic interface device at the target site (at step 4904);and moving the self-propelling lumen-traveling device away from thetarget site while leaving the at least one bioelectromagnetic interfacedevice at the target site (at step 4906).

FIG. 75 is a flow diagram of an expansion of the method of FIG. 74,showing additional details of the method. In some embodiments, themethod may include a preliminary step 5002 of attaching the at least onebioelectromagnetic interface device to the self-propellinglumen-traveling device. The method may include moving at least onebioelectromagnetic interface device through a body tube tree of asubject toward a target site with a self-propelling lumen-travelingdevice (at step 5004). In some embodiments, the method may includemoving the at least one bioelectromagnetic interface device through abody tube tree of a subject toward a target site with a self-propellinglumen-traveling device by pulling the at least one bioelectromagneticinterface device with the self-propelling lumen-traveling device asshown at 5006, while in other embodiments the method may include movingthe at least one bioelectromagnetic interface device through a body tubetree of a subject toward a target site with a self-propellinglumen-traveling device by pushing the at least one bioelectromagneticinterface device with the self-propelling lumen-traveling device, asshown at 5008. The method may include detecting the arrival of the atleast one bioelectromagnetic interface device at the target site (atstep 5010) and releasing the at least one bioelectromagnetic interfacedevice from the self-propelling lumen-traveling device (at step 5012).In some cases the method may include causing the at least onebioelectromagnetic interface device to engage the wall of the body tubetree at the target site (as shown at 5014), and moving theself-propelling lumen-traveling device away from the target site whileleaving the at least one bioelectromagnetic interface device at thetarget site (at step 5016).

FIG. 76 is a flow diagram showing further details of the method of FIG.74. The method includes moving at least one bioelectromagnetic interfacedevice through a body tube tree of a subject toward a target site with aself-propelling lumen-traveling device (at step 5052); detecting thearrival of the at least one bioelectromagnetic interface device at thetarget site (at step 5054); and moving the self-propellinglumen-traveling device away from the target site while leaving the atleast one bioelectromagnetic interface device at the target site (atstep 5056). The body tube tree may be the cardiovascular system, asindicated at 5060, the CSF-space, as indicated at 5062, the respiratorysystem of the subject, as indicated at 5064, the gastrointestinal tractof the subject, as indicated at 5066, of the urogenital tract of thesubject, as indicated at 5068, or various other body lumens that mayprovide access to a stimulation target.

FIG. 77 is a flow diagram of a method of emplacing a bioelectromagneticinterface system including: introducing a plurality ofbioelectromagnetic interface devices into a body tube tree of a subjectvia at least one introduction site at step 5102, at least a portion ofthe bioelectromagnetic interface devices including at least oneelectromagnetic transducer configured for at least one of producing anoutput signal representative of a bioelectromagnetic signal sensed froma target tissue or delivering an electromagnetic stimulus to the targettissue and at least one of a signal processing portion capable ofprocessing the output signal from the electromagnetic transducer or astimulus source capable of producing an electromagnetic stimulus fordelivery to the target tissue with the at least one electromagnetictransducer; and causing the plurality of bioelectromagnetic interfacedevices to travel within the body tube tree to a plurality of targetsites within the body tube tree, at least a portion of the plurality oftarget sites located in the vicinity of at least one target tissue (step5104).

The method may including introducing the plurality of bioelectromagneticinterface devices into the body tube tree via the at least oneintroduction site substantially simultaneously, as indicated at 5108.Alternatively, the method may include introducing the plurality ofbioelectromagnetic interface devices into the body tube tree via the atleast one introduction site in batches, as indicated at 5110. A batch isa group of devices that are introduced substantially simultaneously at asingle location. In another alternative, the method may includeintroducing the plurality of bioelectromagnetic interface devices intothe body tube tree via the at least one introduction site sequentially,as indicated at 5112. In another alternative, the method may includeintroducing the plurality of bioelectromagnetic interface devices intothe body tube tree of the subject via the at least one introduction siteas a linked group of bioelectromagnetic interface devices. For example,the bioelectromagnetic interface devices may be linked to each otherend-to-end in a chain with connectors or graspers of the type depictedin FIGS. 25A and 25B, or each interface device may be attached, eitherpermanently or temporarily, to one or more other interface devices in achain or other configuration by suture material, wire, cable, fiber,etc., for example as depicted in FIG. 72.

The introduction of a single bioelectromagnetic interface device isdepicted in FIG. 64. The introduction of a batch of multiplebioelectromagnetic interface devices into the body tube tree at a singleintroduction site is illustrated in FIG. 66. FIGS. 78A-78B depict theintroduction of a batch of multiple bioelectromagnetic interface devicesinto a body tube tree, showing greater detail. In FIG. 78A, a batch ofmultiple bioelectromagnetic interface devices includingbioelectromagnetic interface devices 5150 a, 5150 b, 5150 c and 5150 dis contained in syringe 5152 prior to delivery into body tube tree 5154.Body tube tree 5154 includes first region 5156 and branches 5158, 5160,5162, and 5164. As shown in FIG. 78B, bioelectromagnetic interfacedevices 5150 a, 5150 b, 5150 c and 5150 d are introduced into firstregion 5156 of body tube tree 5154 as a group, substantiallysimultaneously. As shown in FIG. 78C, bioelectromagnetic interfacedevices 5150 a, 5150 b, 5150 c and 5150 d travel along the routesindicated by the dashed arrows to reach branches 5164, 5160, 5158, and5162, respectively. The same procedure can be carried out at multiplelocations in the body, either simultaneously (by using multiple syringesor equivalents) or in sequence, to deliver multiple batches ofbioelectromagnetic interface devices to the body.

FIG. 79 illustrates a plurality of bioelectromagnetic interface devices5200 a, 5200 b, 5200 c, 5200 d, 5200 e, 5200 f, 5200 g, 5200 h, locatedat a plurality of target sites 5202 a, 5202 b, 5202 c, 5202 d, 5202 e,5202 f, 5202 g, 5202 h, within vasculature 5204 of brain 5206. Thetarget sites 5202 a, 5202 b, 5202 c, 5202 d, 5202 e, 5202 f, 5202 g,5202 h (indicated by dashed circles) are distributed through out brainregion 5208. Multiple bioelectromagnetic interface devices may be usedto record activity from multiple locations, to record multiple signalsfrom a single general area, to stimulate multiple areas, to generatecomplex electromagnetic fields for stimulation, or to perform bothrecording and stimulation, simultaneously or in a desired temporalsequence. Stimulation of a plurality of areas may include stimulation ofspatially proximate areas, e.g., adjacent brain regions, or spatiallyseparated regions of a body.

FIG. 80 is a flow diagram of a method of emplacing a bioelectromagneticinterface system as shown in FIG. 77, which includes: introducing aplurality of bioelectromagnetic interface devices into a body tube treeof a subject via at least one introduction site, at least a portion ofthe bioelectromagnetic interface devices including at least oneelectromagnetic transducer configured for at least one of producing anoutput signal representative of a bioelectromagnetic signal sensed froma target tissue or delivering an electromagnetic stimulus to the targettissue and at least one of a signal processing portion capable ofprocessing the output signal from the electromagnetic transducer or astimulus source capable of producing an electromagnetic stimulus fordelivery to the target tissue with the at least one electromagnetictransducer (step 5252); and causing the plurality of bioelectromagneticinterface devices to travel within the body tube tree to a plurality oftarget sites within the body tube tree, at least a portion of theplurality of target sites located in the vicinity of at least one targettissue (step 5254). The plurality of target sites may spatiallydistributed around the target tissue, as indicated at 5258 in FIG. 80,and illustrated in FIG. 72, or spatially distributed throughout thetarget tissue as indicated at 5260 in FIG. 80, and as illustrated inFIG. 79.

As further shown in FIG. 80, the method may include causing at least aportion of the plurality of bioelectromagnetic interface devices totravel within the body tube tree under their own power, wherein the atleast a portion of the plurality of bioelectromagnetic interface devicesincludes self-propelling devices, as shown at 5262. In some embodiments,the method may include causing at least a portion of the plurality ofbioelectromagnetic interface devices to travel within the body tube treeby moving the at least a portion of the plurality of bioelectromagneticinterface devices through the body tube tree attached to at least onecatheter, as indicated at 5264. An example of emplacement of abioelectromagnetic interface device with a catheter is depicted in FIG.65. Introduction of a device with a catheter is illustrated in FIG. 65.In some embodiments, following placement of a bioelectromagneticinterface device in the body tube tree with a catheter, thebioelectromagnetic interface device may travel from the initialplacement site to a final destination under its own power.

FIG. 81 is a flow diagram of a method of emplacing a bioelectromagneticinterface system as shown in FIG. 77, which includes: introducing aplurality of bioelectromagnetic interface devices into a body tube treeof a subject via at least one introduction site, at least a portion ofthe bioelectromagnetic interface devices including at least oneelectromagnetic transducer configured for at least one of producing anoutput signal representative of a bioelectromagnetic signal sensed froma target tissue or delivering an electromagnetic stimulus to the targettissue and at least one of a signal processing portion capable ofprocessing the output signal from the electromagnetic transducer or astimulus source capable of producing an electromagnetic stimulus fordelivery to the target tissue with the at least one electromagnetictransducer (step 5302); and causing the plurality of bioelectromagneticinterface devices to travel within the body tube tree to a plurality oftarget sites within the body tube tree, at least a portion of theplurality of target sites located in the vicinity of at least one targettissue (step 5304). As indicated at 5308, in some embodiments the targettissue may include at least a portion of the heart of the subject. Insome embodiments, as indicated at 5310, the target tissue may include atleast a portion of the nervous system of the subject, including but notlimited to, the cingulate cortex as indicated in 5312, the fornix asindicated in 5314, the anterior thalamus as indicated in 5316, thesubthalamic nucleus as indicated in 5318, the or the globus pallidusinterna as indicated in 5320. In other embodiments, the target tissuemay include at least a portion of a urogenital tract, as indicated at5322, at least a portion of a muscle, as indicated at 5324, or at leasta portion of a gastrointestinal tract, as indicated at 5326.

FIG. 82 is a flow diagram of an expansion the method of emplacing abioelectromagnetic interface system shown in FIG. 77, which includes:introducing a plurality of bioelectromagnetic interface devices into abody tube tree of a subject via at least one introduction site, at leasta portion of the bioelectromagnetic interface devices including at leastone electromagnetic transducer configured for at least one of producingan output signal representative of a bioelectromagnetic signal sensedfrom a target tissue or delivering an electromagnetic stimulus to thetarget tissue and at least one of a signal processing portion capable ofprocessing the output signal from the electromagnetic transducer or astimulus source capable of producing an electromagnetic stimulus fordelivery to the target tissue with the at least one electromagnetictransducer (step 5352); causing the plurality of bioelectromagneticinterface devices to travel within the body tube tree to a plurality oftarget sites within the body tube tree, at least a portion of theplurality of target sites located in the vicinity of at least one targettissue (step 5354), causing each of at least a portion of the pluralityof bioelectromagnetic interface devices to stop adjacent a respectivetarget site (step 5356), and, optionally, causing each of at least aportion of the plurality of bioelectromagnetic interface devices toengage the wall of the body tube tree adjacent to a respective targetsite (step 5358). In some embodiments, as indicated at 5362, the bodytube tree may be the cardiovascular system of the subject. In otherembodiments, as indicated at 5364, the body tube tree may be therespiratory system of the subject. In still other embodiments, the bodytube tree may be the CSF-space of the subject, as indicated at 5366, theurogenital tract of the subject, as indicated at 5368, or thegastrointestinal tract of the subject, as indicated at 5370.

FIG. 83 is a flow diagram showing further variations of the method ofemplacing a bioelectromagnetic interface system shown generally in FIG.77. The method includes: introducing a plurality of bioelectromagneticinterface devices into a body tube tree of a subject via at least oneintroduction site, at least a portion of the bioelectromagneticinterface devices including at least one electromagnetic transducerconfigured for at least one of producing an output signal representativeof a bioelectromagnetic signal sensed from a target tissue or deliveringan electromagnetic stimulus to the target tissue and at least one of asignal processing portion capable of processing the bioelectromagneticsignal recorded from the target tissue with the at least oneelectromagnetic transducer or a stimulus source capable of producing anelectromagnetic stimulus for delivery to the target tissue with the atleast one electromagnetic transducer (step 5402); causing the pluralityof bioelectromagnetic interface devices to travel within the body tubetree to a plurality of target sites within the body tube tree, at leasta portion of the plurality of target sites located in the vicinity of atleast one target tissue (step 5404). In some embodiments, as shown at5408, the method may include selecting at least a portion of theplurality of target sites based upon anatomical information. In someembodiments, as shown at 5410, the method may include selecting at leasta portion of the plurality of target sites based upon measurement of oneor more physiological parameters, which might be, for example, a signalcharacteristic of a selected region of the nervous system, as shown at5412, or a selected region of the heart, as shown at 5414. In someembodiments, as shown at 5416, the one or more physiological parametersmay include a signal-to-noise ratio indicative of good signaltransduction path between at least a portion of the one or morebioelectromagnetic interface devices and the stimulation target.

FIG. 84 is a flow diagram including further variations of the method ofemplacing a bioelectromagnetic interface system shown generally in FIG.77. The method includes: introducing a plurality of bioelectromagneticinterface devices into a body tube tree of a subject via at least oneintroduction site, at least a portion of the bioelectromagneticinterface devices including at least one configured for at least one ofproducing an output signal representative of a bioelectromagnetic signalsensed from a target tissue or delivering an electromagnetic stimulus tothe target tissue and at least one of a signal processing portioncapable of processing the bioelectromagnetic signal recorded from thetarget tissue with the at least one electromagnetic transducer or astimulus source capable of producing an electromagnetic stimulus fordelivery to the target tissue with the at least one electromagnetictransducer (step 5452); causing the plurality of bioelectromagneticinterface devices to travel within the body tube tree to a plurality oftarget sites within the body tube tree, at least a portion of theplurality of target sites located in the vicinity of at least one targettissue (step 5454). In addition, the method may include delivering anelectromagnetic stimulus to the stimulation target with at least aportion of the one or more bioelectromagnetic interface devices, at5456.

As shown at 5458 of FIG. 84, the method may include detecting abioelectric signal from the stimulation target or at least one regionassociated therewith and delivering the electromagnetic stimulus to thestimulation target with at least a portion of the one or morebioelectromagnetic interface devices in response to detecting thebioelectric signal from the stimulation target or the at least oneregion associated therewith. Alternatively, or in addition, the methodmay include detecting a biomagnetic signal from the stimulation targetor at least one region associated therewith and delivering theelectromagnetic stimulus to the stimulation target with at least aportion of the one or more bioelectromagnetic interface devices inresponse to detecting the biomagnetic signal from the stimulation targetor the at least one region associated therewith, as shown at 5460. Inanother alternative, the method may include detecting a biochemicalsignal from the stimulation target or at least one region associatedtherewith and delivering the electromagnetic stimulus to the stimulationtarget with at least a portion of the one or more bioelectromagneticinterface devices in response to detecting the biochemical signal fromthe stimulation target or the at least one region associated therewith,as shown at 5462. Biochemical signals may include signals from varioustypes of biosensors, indicating concentration of neurotransmitters,direct or indirect indicators of metabolic activity, pH, cell-signalingmaterials, and other biochemical signals indicating a condition of thestimulation target and/or indication for delivery of stimulation to thestimulation target.

In another alternative, the method may include detecting a biophysicalsignal from the stimulation target or at least one region associatedtherewith and delivering the electromagnetic stimulus to the stimulationtarget with at least a portion of the one or more bioelectromagneticinterface devices in response to detecting the biophysical signal fromthe stimulation target or the at least one region associated therewith,as shown at 5464.

In some embodiments, one or more remote portions may be used, and themethod may include detecting a remote control signal and delivering theelectromagnetic stimulus to the stimulation target with at least aportion of the bioelectromagnetic interface devices in response todetecting the remote control signal, as a shown at 5466. In otherembodiments, the method may include delivering the electromagneticstimulus to the stimulation target with at least a portion of thebioelectromagnetic interface devices based upon a pre-programmedstimulation pattern, as shown at 5468.

FIG. 85 is a flow diagram of a method of emplacing a neural stimulationdevice, which may include causing a self-propelling neural stimulationdevice to travel within a body tube tree of a subject toward a targetsite (at step 5502); if a branch point including two or more brancheswithin the body tube tree is reached by the self-propelling neuralstimulation device, causing the self-propelling neural stimulationdevice to enter a branch leading toward the target site (at step 5504);and causing the self-propelling neural stimulation device to stoptraveling upon reaching the target site (at 5506). As noted elsewhereherein, various applications are known for neural stimulation devicesand systems. The method may be used for emplacing a single neuralstimulation device at a time, or for expanding to emplace multipleneural stimulation devices. In one variant, the method may includecarrying at least one additional neural stimulation device with theself-propelling neural stimulation device. The neural stimulationdevices may remain connected during use, or the method may includeresealing the at least one additional neural stimulation device from theself-propelling neural stimulation device.

FIG. 86 is a flow diagram showing further details of a method asoutlined in FIG. 85. The method may include introducing theself-propelling neural stimulation device into the body tube tree of asubject (at step 5552), causing a self-propelling neural stimulationdevice to travel within a body tube tree of a subject toward a targetsite (at step 5554); if a branch point including two or more brancheswithin the body tube tree is reached by the self-propelling neuralstimulation device, causing the self-propelling neural stimulationdevice to enter a branch leading toward the target site (at step 5556);causing the self-propelling neural stimulation device to stop travelingupon reaching the target site (at 5558), and, optionally, causing theself-propelling neural stimulation device to engage the wall of the bodytube tree at the target site (at step 5560). The body tube tree may bethe vascular system of the subject, as indicated at 5564, therespiratory system of the subject, as indicated at 5566, or theCSF-space of the subject, as indicated at 5568, for example.

FIG. 87 is a flow diagram showing further details of a method asoutlined in FIG. 86. The method may include introducing theself-propelling neural stimulation device into the body tube tree of asubject (at step 5602), causing a self-propelling neural stimulationdevice to travel within a body tube tree of a subject toward a targetsite (at step 5604); if a branch point including two or more brancheswithin the body tube tree is reached by the self-propelling neuralstimulation device, causing the self-propelling neural stimulationdevice to enter a branch leading toward the target site (at step 5606);causing the self-propelling neural stimulation device to stop travelingupon reaching the target site (at 5608), and, optionally, causing theself-propelling neural stimulation device to engage the wall of the bodytube tree at the target site (at step 5610). The method may includecausing the self-propelling neural stimulation device to travel withinthe body tube tree toward a target site located within a chamber of theheart of the subject, as indicated at 5614. In another embodiment, themethod may include causing the self-propelling neural stimulation deviceto travel within the body tube tree toward a target site located withinthe brain of the subject, as indicated at 5616. In another embodiment,the method may include causing the self-propelling neural stimulationdevice to travel within the body tube tree toward a target site locatedwithin the spinal canal of the subject, as indicated at 5618. In anotherembodiment, the method may include causing the self-propelling neuralstimulation device to travel within the body tube tree toward a targetsite located within the gastrointestinal tract of the subject, asindicated at 5620. In still another embodiment, the method may includecausing the self-propelling neural stimulation device to travel withinthe body tube tree toward a target site located within the urogenitalsystem of the subject, as indicated at 5622. And in yet anotherembodiment, the method may include causing the self-propelling neuralstimulation device to travel within the body tube tree toward a targetsite located within the musculature of the subject, as indicated at5624.

FIG. 88 is a flow diagram showing a further expansion of the method ofFIG. 85. The method includes selecting a target site in proximity to astimulation target (at step 5652) and performing one or more ofadjusting the size of the self-propelling neural stimulation device tofit within the target site (at 5664) or selecting a self-propellingneural stimulation device sized to fit within a target size (at 5666),e.g. by selecting the self-propelling neural stimulation device from anassortment of self-propelling neural stimulation devices of differentsizes (at 5668). The method may also include the steps of causing aself-propelling neural stimulation device to travel within a body tubetree of a subject toward a target site (at 5670), if a branch pointincluding two or more branches within the body tube tree is reached bythe self-propelling neural stimulation device, causing theself-propelling neural stimulation device to enter a branch leadingtoward the target site (at 5672), and causing the self-propelling neuralstimulation device to stop traveling upon reaching the target site (at5674). In some embodiments, the method may include causing theself-propelling neural stimulation device to resume traveling, asindicated at 5676. The self-propelling neural stimulation device may bean electromagnetic stimulation device, as indicated at 5678, a magneticstimulation device, as indicated at 5680, an optical stimulation device,as indicated at 5682, or a chemical stimulation device, as indicated at5684.

FIG. 89 is a flow diagram showing a further expansion of the method ofFIG. 85, including the steps of causing a self-propelling neuralstimulation device to travel within a body tube tree of a subject towarda target site at 5702; if a branch point including two or more brancheswithin the body tube tree is reached by the self-propelling neuralstimulation device, causing the self-propelling neural stimulationdevice to enter a branch leading toward the target site at 5704; andcausing the self-propelling neural stimulation device to stop travelingupon reaching the target site at 5706. The method may include detectingthe branch point with a sensor on the self-propelling neural stimulationdevice, as indicated at 5710. As indicated at 5712, the method mayinclude causing the self-propelling neural stimulation device to travelwithin the body tube tree under the control of a control system locatedat least in part on the self-propelling neural stimulation device.Alternatively, the method may include causing the self-propelling neuralstimulation device to travel within the body tube tree under the controlof a remote portion, as indicated at 5714. The method may includecausing the self-propelling neural stimulation device to stop travelingupon reaching the target site by discontinuing propulsion of theself-propelling neural stimulation device, as shown at 5716, by causingthe self-propelling neural stimulation device to stop traveling uponreaching the target site by applying a force to oppose propulsion of theself-propelling neural stimulation device, as shown at 5718, or byengaging the wall of the body tube tree at the target site, as shown at5720. The self-propelling neural stimulation device may be caused toengage a wall of the body tube tree by causing at least a portion of theself-propelling neural stimulation device to expand to form a pressurefit with the wall of the body tube tree, as indicated at 5722, byreleasing an adhesive material from the self-propelling neuralstimulation device, as indicated at 5724, or extending at least one clawor barb-like structure from the self-propelling neural stimulationdevice to penetratingly engage the wall of the body tube tree, asindicated at 5726. Examples of such structures are illustrated in FIGS.5A, 5B, and 8B, for example.

FIG. 90 depicts steps of method of emplacing a bioelectromagnetic signalsensing device, which may include: causing a self-propellingbioelectromagnetic signal sensing device to travel within a body tubetree of a subject toward a target site (step 5752); if a branch pointincluding two or more branches within the body tube tree may be reachedby the self-propelling bioelectromagnetic signal sensing device, causingthe self-propelling bioelectromagnetic signal sensing device to enter abranch leading toward the target site (step 5754); and causing theself-propelling bioelectromagnetic signal sensing device to stoptraveling upon reaching the target site (step 5756).

In some embodiments, sensing of bioelectromagnetic signals withbioelectromagnetic signal sensing devices as described herein may beused in research or diagnostic applications. In some embodiments,sensing of bioelectromagnetic signals may be used in combination withstimulation (electrical, magnetic, chemical, optical, etc.), delivery ofdrugs, or various treatments, stimuli, etc. to provide a therapeutic orbeneficial effect, for providing control or feedback. Such applicationsare provided by way of example, and are not intended to be limiting.

FIG. 91 shows an expanded version of the method of FIG. 90, whichincludes introducing the self-propelling bioelectromagnetic signalsensing device into the body tube tree of a subject at 5802; causing theself-propelling bioelectromagnetic signal sensing device to travelwithin a body tube tree of a subject toward a target site at 5804; if abranch point including two or more branches within the body tube tree isreached by the self-propelling bioelectromagnetic signal sensing device,causing the self-propelling bioelectromagnetic signal sensing device toenter a branch leading toward the target site at 5806 causing theself-propelling bioelectromagnetic signal sensing device to stoptraveling upon reaching the target site at 5808; and causing theself-propelling bioelectromagnetic signal sensing device to engage thewall of the body tube tree at the target site at 5810. The body tubetree may be any of various body tube trees, including, but not limitedto, a vascular system of the subject, as indicated at 5814, arespiratory system of the subject, as indicated at 5816, or a CSF-spaceof the subject, as indicated at 5818. The bioelectromagnetic signalsensing device may be caused to travel within the body tube tree underthe control of a control system located at least in part on theself-propelling bioelectromagnetic signal sensing device, as indicatedat 5820, or alternatively, the method may include causing theself-propelling bioelectromagnetic signal sensing device to travelwithin the body tube tree under the control of a remote portion, asindicated at 5822.

FIG. 92 provides still further details of a method as shown in FIG. 90.The method includes selecting a target site in proximity to abioelectromagnetic signal source (step 5852); causing a self-propellingbioelectromagnetic signal sensing device to travel within a body tubetree of a subject toward a target site (step 5854); if a branch pointincluding two or more branches within the body tube tree is reached bythe self-propelling bioelectromagnetic signal sensing device, causingthe self-propelling bioelectromagnetic signal sensing device to enter abranch leading toward the target site (step 5856); and causing theself-propelling bioelectromagnetic signal sensing device to stoptraveling upon reaching the target site (step 5858). As in variouspreviously described embodiments, the method may include a step ofengaging a wall of the body tube tree by various methods including, butnot limited to, causing at least a portion of the self-propellingbioelectromagnetic signal sensing device to expand to form a pressurefit with the wall of the body tube tree (as shown at 5860), releasing anadhesive material from the self-propelling bioelectromagnetic signalsensing device (as shown at 5862), or extending at least one claw orbarb-like structure from the self-propelling bioelectromagnetic signalsensing device to penetratingly engage the wall of the body tube tree(as shown at 5864). Step 5854 may include causing the self-propellingbioelectromagnetic signal sensing device to travel with the body tubetree toward a target site located within a chamber of a heart of thesubject (as shown at 5868), within the brain of the subject, of thesubject (as shown at 5870), within a spinal canal of the subject (asshown at 5872), within a gastrointestinal tract of the subject (as shownat 5874), within a urogenital system of the subject (as shown at 5876),or within a musculature of the subject of the subject (as shown at5878). A target site may be selected that is in proximity to abioelectromagnetic signal source, for example, a target site within achamber of the heart may be selected if a signal is to be detected fromthe heart, a target site within a cerebral ventrical or a blood vesselin the brain may be selected for detecting a signal from a region of thebrain, and so on. As shown at 5880, the method may include detecting thebranch point with a sensor on the self-propelling bioelectromagneticsignal sensing device. Various types of signals may provide informationabout the presence of a branch point, including, for example, opticalsignals, acoustic signals, and electromagnetic signals, among others.

FIG. 93 is a flow diagram showing a further variant of the method ofFIG. 90, which includes the steps of causing a self-propellingbioelectromagnetic signal sensing device to travel within a body tubetree of a subject toward a target site (step 5886), causing aself-propelling bioelectromagnetic signal sensing device to travelwithin a body tube tree of a subject toward a target site (step 5888),and sensing a bioelectromagnetic signal with the self-propellingbioelectromagnetic signal sensing device (step 5890). In someembodiments, the method may include, sensing a plurality ofbioelectromagnetic signals with the self-propelling bioelectromagneticsignal sensing device, wherein each of the plurality ofbioelectromagnetic signals is sensed with a respective electromagnetictransducer of a plurality of electromagnetic transducers carried by theself-propelling bioelectromagnetic signal sensing device, as indicatedat 5892. The method may also include causing the self-propellingbioelectromagnetic signal sensing device to stop traveling upon reachingthe target site (step 5894) and causing the self-propellingbioelectromagnetic signal sensing device to resume traveling (step5896).

Another application for methods and devices as described herein is incardiac stimulation. FIG. 94 shows steps of method for emplacing acardiac stimulation device. The method may include causing aself-propelling cardiac stimulation device to travel within the bodytube tree of a subject toward a target site at 5902; if a branch pointincluding two or more branches within the body tube tree is reached bythe self-propelling cardiac stimulation device, causing theself-propelling cardiac stimulation device to enter a branch leadingtoward the target site at 5904; and causing the self-propelling cardiacstimulation device to stop traveling upon reaching the target site at5906.

FIG. 95 shows an expansion of the method of FIG. 94, which includesintroducing the self-propelling cardiac stimulation device into the bodytube tree of a subject (step 5952); selecting a target site in proximityto a stimulation target (step 5954); causing a self-propelling cardiacstimulation device to travel within the body tube tree of a subjecttoward a target site at 5956; if a branch point including two or morebranches within the body tube tree is reached by the self-propellingcardiac stimulation device, causing the self-propelling cardiacstimulation device to enter a branch leading toward the target site at5958; and causing the causing the self-propelling cardiac stimulationdevice to stop traveling upon reaching the target site at 5960. Theself-propelling cardiac stimulation device may be introduced into a bodytube tree of the subject at step 5952 by injection, or by being releasedfrom a catheter, for example. In some embodiments, the body tube treemay be the vascular system of the subject, as indicated in 5964; asillustrated in FIG. 64, a self-propelling cardiac stimulation deviceintroduced into the vascular system (e.g. via a vein in the arm) cantravel to the heart, where it may be used to deliver stimulation withina chamber of the heart. The self-propelling cardiac stimulation devicemay be an electromagnetic stimulation device, as indicated in 5966, amagnetic stimulation device, as indicated in 5968, an opticalstimulation device, as indicated in 5970, or a chemical stimulationdevice, as indicated in 5972. The stimulation target referenced in step5954 may be, for example, a particular region of the heart, and thetarget site may be a particular location within the heart, on theexterior of the heart, or in a blood vessel supplying the heart, forexample. As described generally elsewhere herein, the method may includecausing the self-propelling cardiac stimulation device to travel withinthe body tube tree under the control of a control system located atleast in part on the self-propelling cardiac stimulation device, orcausing the self-propelling cardiac stimulation device to travel withinthe body tube tree under the control of a remote portion. FIG. 95 alsodepicts two additional optional steps: in some embodiments, as indicatedin 5974, the method may include pushing one or more additional cardiacstimulation devices with the self-propelling cardiac stimulation device,while in other embodiments, as indicated in 5976, the method may includepulling one or more additional cardiac stimulation devices with theself-propelling cardiac stimulation device.

A further variant of the method of emplacing a cardiac stimulationdevice outlined in FIG. 94 is shown in FIG. 96. The method may includeselecting a self-propelling cardiac stimulation device that is sized tofit within the target site, as indicated at 6002. This may beaccomplished, for example by selecting the self-propelling cardiacstimulation device from an assortment of self-propelling cardiacstimulation devices of different sizes, as indicated in 6004.Alternatively, the method may include adjusting the size of theself-propelling cardiac stimulation device to fit within the targetsite, as indicated at 6006. The method may include causing aself-propelling cardiac stimulation device to travel within the bodytube tree of a subject toward a target site at 6008; if a branch pointincluding two or more branches within the body tube tree is reached bythe self-propelling cardiac stimulation device, causing theself-propelling cardiac stimulation device to enter a branch leadingtoward the target site at 6010; and causing the self-propelling cardiacstimulation device to stop traveling upon reaching the target site at6012. The method may further include causing the self-propelling cardiacstimulation device to engage the wall of the body tube tree at thetarget site, at 6014. The method may include detecting the branch pointwith a sensor on the self-propelling cardiac stimulation device, asindicated at 6018.

The method may include engaging a wall of the body tube tree by causingat least a portion of the self-propelling cardiac stimulation device toexpand to form a pressure fit with the wall of the body tube tree, asindicated at 6020, by releasing an adhesive material from theself-propelling cardiac stimulation device, as indicated at 6022, or byextending at least one claw or barb-like structure from theself-propelling cardiac stimulation device to penetratingly engage thewall of the body tube tree, as indicated at 6024.

Those having skill in the art will recognize that the state of the arthas progressed to the point where there is little distinction leftbetween hardware and software implementations of aspects of systems; theuse of hardware or software is generally (but not always, in that incertain contexts the choice between hardware and software can becomesignificant) a design choice representing cost vs. efficiency tradeoffs.Those having skill in the art will appreciate that there are variousvehicles by which processes and/or systems and/or other technologiesdescribed herein can be effected (e.g., hardware, software, and/orfirmware), and that the preferred vehicle will vary with the context inwhich the processes and/or systems and/or other technologies aredeployed. For example, if an implementer determines that speed andaccuracy are paramount, the implementer may opt for a mainly hardwareand/or firmware vehicle; alternatively, if flexibility is paramount, theimplementer may opt for a mainly software implementation; or, yet againalternatively, the implementer may opt for some combination of hardware,software, and/or firmware. Hence, there are several possible vehicles bywhich the processes and/or devices and/or other technologies describedherein may be effected, none of which is inherently superior to theother in that any vehicle to be utilized is a choice dependent upon thecontext in which the vehicle will be deployed and the specific concerns(e.g., speed, flexibility, or predictability) of the implementer, any ofwhich may vary. Those skilled in the art will recognize that opticalaspects of implementations will typically employ optically-orientedhardware, software, and or firmware.

The foregoing detailed description has set forth various embodiments ofthe devices and/or processes via the use of block diagrams, flowcharts,and/or examples. Insofar as such block diagrams, flowcharts, and/orexamples contain one or more functions and/or operations, it will beunderstood by those within the art that each function and/or operationwithin such block diagrams, flowcharts, or examples can be implemented,individually and/or collectively, by a wide range of hardware, software,firmware, or virtually any combination thereof. It will further beunderstand that method steps may be presented in a particular order inflowcharts, and/or examples herein, but are not necessarily limited tobeing performed in the presented order. For example, steps may beperformed simultaneously, or in a different order than presented herein,and such variations will be apparent to one of skill in the art in lightof this disclosure. In one embodiment, several portions of the subjectmatter described herein may be implemented via Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs),digital signal processors (DSPs), or other integrated formats. However,those skilled in the art will recognize that some aspects of theembodiments disclosed herein, in whole or in part, can be equivalentlyimplemented in integrated circuits, as one or more computer programsrunning on one or more computers (e.g., as one or more programs runningon one or more computer systems), as one or more programs running on oneor more processors (e.g., as one or more programs running on one or moremicroprocessors), as firmware, or as virtually any combination thereof,and that designing the circuitry and/or writing the code for thesoftware and or firmware would be well within the skill of one of skillin the art in light of this disclosure. In addition, those skilled inthe art will appreciate that the mechanisms of the subject matterdescribed herein are capable of being distributed as a program productin a variety of forms, and that an illustrative embodiment of thesubject matter described herein applies regardless of the particulartype of signal bearing medium used to actually carry out thedistribution. Examples of a signal bearing medium include, but are notlimited to, the following: a recordable type medium such as a floppydisk, a hard disk drive, a Compact Disc (CD), a Digital Video Disk(DVD), a digital tape, a computer memory, etc.; and a transmission typemedium such as a digital and/or an analog communication medium (e.g., afiber optic cable, a waveguide, a wired communications link, a wirelesscommunication link, etc.).

In a general sense, those skilled in the art will recognize that thevarious embodiments described herein can be implemented, individuallyand/or collectively, by various types of electro-mechanical systemshaving a wide range of electrical components such as hardware, software,firmware, or virtually any combination thereof; and a wide range ofcomponents that may impart mechanical force or motion such as rigidbodies, spring or torsional bodies, hydraulics, and electro-magneticallyactuated devices, or virtually any combination thereof. Consequently, asused herein “electro-mechanical system” includes, but is not limited to,electrical circuitry operably coupled with a transducer (e.g., anactuator, a motor, a piezoelectric crystal, etc.), electrical circuitryhaving at least one discrete electrical circuit, electrical circuitryhaving at least one integrated circuit, electrical circuitry having atleast one application specific integrated circuit, electrical circuitryforming a general purpose computing device configured by a computerprogram (e.g., a general purpose computer configured by a computerprogram which at least partially carries out processes and/or devicesdescribed herein, or a microprocessor configured by a computer programwhich at least partially carries out processes and/or devices describedherein), electrical circuitry forming a memory device (e.g., forms ofrandom access memory), electrical circuitry forming a communicationsdevice (e.g., a modem, communications switch, or optical-electricalequipment), and any non-electrical analog thereto, such as optical orother analogs. Those skilled in the art will recognize thatelectro-mechanical as used herein is not necessarily limited to a systemthat has both electrical and mechanical actuation except as context maydictate otherwise. Non-electrical analogs of electrical circuitry mayinclude fluid circuitry, electro-mechanical circuitry, mechanicalcircuitry, and various combinations thereof.

In a general sense, those skilled in the art will recognize that thevarious aspects described herein which can be implemented, individuallyand/or collectively, by a wide range of hardware, software, firmware, orany combination thereof can be viewed as being composed of various typesof “electrical circuitry.” Consequently, as used herein “electricalcircuitry” includes, but is not limited to, electrical circuitry havingat least one discrete electrical circuit, electrical circuitry having atleast one integrated circuit, electrical circuitry having at least oneapplication specific integrated circuit, electrical circuitry forming ageneral purpose computing device configured by a computer program (e.g.,a general purpose computer configured by a computer program which atleast partially carries out processes and/or devices described herein,or a microprocessor configured by a computer program which at leastpartially carries out processes and/or devices described herein),electrical circuitry forming a memory device (e.g., forms of randomaccess memory), and/or electrical circuitry forming a communicationsdevice (e.g., a modem, communications switch, or optical-electricalequipment). Those having skill in the art will recognize that thesubject matter described herein may be implemented in an analog ordigital fashion or some combination thereof.

One skilled in the art will recognize that the herein describedcomponents (e.g., steps), devices, and objects and the discussionaccompanying them are used as examples for the sake of conceptualclarity and that various configuration modifications are within theskill of those in the art. Consequently, as used herein, the specificexemplars set forth and the accompanying discussion are intended to berepresentative of their more general classes. In general, use of anyspecific exemplar herein is also intended to be representative of itsclass, and the non-inclusion of such specific components (e.g., steps),devices, and objects herein should not be taken as indicating thatlimitation is desired.

With respect to the use of substantially any plural and/or singularterms herein, those having skill in the art can translate from theplural to the singular and/or from the singular to the plural as isappropriate to the context and/or application. The varioussingular/plural permutations are not expressly set forth herein for sakeof clarity.

The herein described subject matter sometimes illustrates differentcomponents contained within, or connected with, different othercomponents. It is to be understood that such depicted architectures aremerely exemplary, and that in fact many other architectures can beimplemented which achieve the same functionality. In a conceptual sense,any arrangement of components to achieve the same functionality iseffectively “associated” such that the desired functionality isachieved. Hence, any two components herein combined to achieve aparticular functionality can be seen as “associated with” each othersuch that the desired functionality is achieved, irrespective ofarchitectures or intermedial components. Likewise, any two components soassociated can also be viewed as being “operably connected”, or“operably coupled”, to each other to achieve the desired functionality,and any two components capable of being so associated can also be viewedas being “operably couplable”, to each other to achieve the desiredfunctionality. Specific examples of operably couplable include but arenot limited to physically mateable and/or physically interactingcomponents and/or wirelessly interactable and/or wirelessly interactingcomponents and/or logically interacting and/or logically interactablecomponents.

While particular aspects of the present subject matter described hereinhave been shown and described, it will be apparent to those skilled inthe art that, based upon the teachings herein, changes and modificationsmay be made without departing from the subject matter described hereinand its broader aspects and, therefore, the appended claims are toencompass within their scope all such changes and modifications as arewithin the true spirit and scope of the subject matter described herein.Furthermore, it is to be understood that the invention is defined by theappended claims. It will be understood by those within the art that, ingeneral, terms used herein, and especially in the appended claims (e.g.,bodies of the appended claims) are generally intended as “open” terms(e.g., the term “including” should be interpreted as “including but notlimited to,” the term “having” should be interpreted as “having atleast,” the term “includes” should be interpreted as “includes but isnot limited to,” etc.). It will be further understood by those withinthe art that if a specific number of an introduced claim recitation isintended, such an intent will be explicitly recited in the claim, and inthe absence of such recitation no such intent is present. For example,as an aid to understanding, the following appended claims may containusage of the introductory phrases “at least one” and “one or more” tointroduce claim recitations. However, the use of such phrases should notbe construed to imply that the introduction of a claim recitation by theindefinite articles “a” or “an” limits any particular claim containingsuch introduced claim recitation to inventions containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should typically be interpreted to mean “atleast one” or “one or more”); the same holds true for the use ofdefinite articles used to introduce claim recitations. In addition, evenif a specific number of an introduced claim recitation is explicitlyrecited, those skilled in the art will recognize that such recitationshould typically be interpreted to mean at least the recited number(e.g., the bare recitation of “two recitations,” without othermodifiers, typically means at least two recitations, or two or morerecitations). Furthermore, in those instances where a conventionanalogous to “at least one of A, B, and C, etc.” is used, in generalsuch a construction is intended in the sense one having skill in the artwould understand the convention (e.g., “a system having at least one ofA, B, and C” would include but not be limited to systems that have Aalone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). In those instances where aconvention analogous to “at least one of A, B, or C, etc.” is used, ingeneral such a construction is intended in the sense one having skill inthe art would understand the convention (e.g., “a system having at leastone of A, B, or C” would include but not be limited to systems that haveA alone, B alone, C alone, A and B together, A and C together, B and Ctogether, and/or A, B, and C together, etc.). It will be furtherunderstood by those within the art that virtually any disjunctive wordand/or phrase presenting two or more alternative terms, whether in thedescription, claims, or drawings, should be understood to contemplatethe possibilities of including one of the terms, either of the terms, orboth terms. For example, the phrase “A or B” will be understood toinclude the possibilities of “A” or “B” or “A and B.”

While various aspects and embodiments have been disclosed herein, otheraspects and embodiments will be apparent to those skilled in the art.The various aspects and embodiments disclosed herein are for purposes ofillustration and are not intended to be limiting, with the true scopeand spirit being indicated by the following claims.

1. A lumen-traveling device, comprising: a propelling mechanism capableof producing directional movement of the lumen-traveling device througha body lumen; a steering mechanism capable of modifying a direction ofmovement of the lumen-traveling device; at least one electromagnetictransducer configured for at least one of producing an output signalrepresentative of a bioelectromagnetic signal sensed from a targettissue or delivering an electromagnetic stimulus to the target tissue;and at least one of a signal processing portion capable of processingthe output signal from the electromagnetic transducer or a stimulussource capable of producing an electromagnetic stimulus for delivery tothe target tissue with the electromagnetic transducer. 2.-12. (canceled)13. The lumen-traveling device of claim 1, including at least onewall-engaging structure capable of engaging a wall of the body lumen tosecure the lumen-traveling stimulation device with respect to the wallof the body lumen in the vicinity of the target tissue.
 14. Thelumen-traveling device of claim 1, including a structural elementconfigured to at least intermittently permit the movement of fluidthrough the body lumen past the lumen-traveling device.
 15. Thelumen-traveling device of claim 1, including at least oneelectromagnetic transducer configured for producing an output signalrepresentative of a bioelectromagnetic signal sensed from a targettissue, and at least one signal processing portion capable of processingthe output signal from the electromagnetic transducer.
 16. Thelumen-traveling device of claim 1, including at least oneelectromagnetic transducer configured for delivering an electromagneticstimulus to the target tissue, and at least one stimulus source capableof producing an electromagnetic stimulus for delivery to the targettissue with the electromagnetic transducer.
 17. The lumen-travelingdevice of claim 1, including at least one electromagnetic transducerconfigured for producing an output signal representative of abioelectromagnetic signal sensed from a target tissue, at least oneelectromagnetic transducer configured for delivering an electromagneticstimulus to the target tissue; at least one signal processing portioncapable of processing the output signal from the electromagnetictransducer, and at least one stimulus source capable of producing anelectromagnetic stimulus for delivery to the target tissue with theelectromagnetic transducer.
 18. The lumen-traveling device of claim 17,including at least one electromagnetic transducer configured forproducing an output signal representative of a bioelectromagnetic signalsensed from a target tissue and delivering an electromagnetic stimulusto the target tissue.
 19. The lumen-traveling device of claim 1,including a receiver configured to receive a signal from a remoteportion. 20.-21. (canceled)
 22. The lumen-traveling device of claim 1,including a power source. 23.-50. (canceled)
 51. The lumen-travelingdevice of claim 1, including: multiple electromagnetic transducersconfigured for at least one of producing an output signal representativeof a bioelectromagnetic signal sensed from the target tissue ordelivering an electromagnetic stimulus to the target tissue.
 52. Alumen-traveling device, comprising: a propelling mechanism capable ofproducing directional movement of the lumen-traveling device through abody lumen; a steering mechanism capable of modifying a direction ofmovement of the lumen-traveling device; at least one electromagnetictransducer configured for at least one of producing an output signalrepresentative of a bioelectromagnetic signal sensed from a targettissue or delivering an electromagnetic stimulus to the target tissue;at least one of a signal processing portion capable of processing theoutput signal from the electromagnetic transducer or a stimulus sourcecapable of producing an electromagnetic stimulus for delivery to thetarget tissue with the electromagnetic transducer; and a sensor capableof sensing a local condition and generating a sense signal. 53.-61.(canceled)
 62. The lumen-traveling device of claim 1, wherein thestimulus source is capable of producing an electromagnetic stimulus fordelivery to the target tissue with the electromagnetic transducer atleast in part in response to the sense signal from the sensor.
 63. Amethod of emplacing a bioelectromagnetic signal sensing device,comprising: causing a self-propelling bioelectromagnetic signal sensingdevice to travel within a body tube tree of a subject toward a targetsite; if a branch point including two or more branches within the bodytube tree is reached by the self-propelling bioelectromagnetic signalsensing device, causing the self-propelling bioelectromagnetic signalsensing device to enter a branch leading toward the target site; andcausing the self-propelling bioelectromagnetic signal sensing device tostop traveling upon reaching the target site. 64.-83. (canceled)
 84. Themethod of claim 1, including sensing a plurality of bioelectromagneticsignals with the self-propelling bioelectromagnetic signal sensingdevice, wherein each of the plurality bioelectromagnetic signals issensed with a respective electromagnetic transducer of a plurality ofelectromagnetic transducers carried by the self-propellingbioelectromagnetic signal sensing device.
 85. The lumen-traveling deviceof claim 1, wherein the at least one electromagnetic transducer includesat least one of an electrode, a coil, a Hall effect sensor, an antenna,an electromagnetic field source, an ion-sensitive device, a lightsource, a laser diode, a laser, a light emitting diode or a photodiode.86. The lumen-traveling device of claim 1, including at least one ofcontrol circuitry carried by the lumen-traveling device or controlcircuitry located at least in part on the lumen-traveling device. 87.The lumen-traveling device of claim 22, wherein the power sourceincludes at least one of a battery, a microbattery, a fuel cell, abiofuel cell, an inductively driven power receiving structure driven bya remotely applied electromagnetic field, an energy scavenging device,an energy scavenging device capable of transducing energy from bloodflow, an energy scavenging device capable of transducing energy fromheart motion, an energy scavenging device capable of transducing energyfrom gastrointestinal tract motion, an energy scavenging device capableof transducing energy from pulmonary motion, or an energy scavengingdevice capable of transducing energy from muscle motion.
 88. Thelumen-traveling device of claim 1, wherein the lumen-traveling device issized to fit within at least one of a blood vessel in a brain or achamber of a heart.
 89. The lumen-traveling device of claim 1, includingat least one stimulus source capable of producing an electromagneticstimulus for delivery to the target tissue with the electromagnetictransducer, wherein the electromagnetic stimulus is adapted for at leastone of controlling or modifying heart activity or controlling ormodifying neural activity.
 90. The lumen-traveling device of claim 1,including at least one stimulus source capable of producing anelectromagnetic stimulus for delivery to the target tissue with theelectromagnetic transducer, wherein the electromagnetic stimulus is atleast one of a depolarizing stimulus sufficient to producedepolarization of at least a portion of the target tissue, ahyperpolarizing stimulus sufficient to produce hyperpolarization of atleast a portion of the target tissue, a promoting stimulus sufficient toproduce a functionally promoting effect in at least a portion of thetarget tissue, or an inhibiting stimulus sufficient to produce afunctionally inhibiting effect in at least a portion of the targettissue.
 91. The lumen-traveling device of claim 1, including at leastone stimulus source capable of at least one of producing anelectromagnetic stimulus for delivery to the target tissue with theelectromagnetic transducer based at least in part upon a pre-programmedstimulation pattern or producing an electromagnetic stimulus fordelivery to the target tissue with the electromagnetic transducer atleast in part in response to a signal received from a remote portion.92. The lumen-traveling device of claim 1, including: at least onesignal processing portion capable of processing the output signal fromthe electromagnetic transducer, wherein the at least one signalprocessing portion is capable of processing the output signal from theelectromagnetic transducer by at least one of amplifying the outputsignal, filtering the output signal, or performing featuredetection/pattern recognition on the output signal.
 93. Thelumen-traveling device of claim 1, including: at least one signalprocessing portion capable of processing the output signal from theelectromagnetic transducer; and at least one of a data storage locationconfigured for storing an output of the at least one signal processingportion or a transmitter configured to transmit an output of the atleast one signal processing portion to a remote location.
 94. Thelumen-traveling device of claim 1, including: at least one transmitterconfigured to transmit information to a remote location, wherein theinformation relates to at least one of the status of the lumen-travelingdevice, the location or position of the lumen-traveling device, anaction taken by the lumen-traveling device, or the delivery of theelectromagnetic stimulus to the target tissue.
 95. The lumen-travelingdevice of claim 1, wherein the sensor includes at least one of anoptical sensor, an imaging device, a thermal sensor, a chemical sensor,an electrical sensor, or a magnetic sensor.
 96. The lumen-travelingdevice of claim 1, wherein the local condition is indicative of at leastone of proximity to the target tissue or an anatomical feature.
 97. Themethod of claim 1, including at least one of introducing theself-propelling bioelectromagnetic signal sensing device into the bodytube tree of the subject or causing the self-propellingbioelectromagnetic signal sensing device to engage a wall of the bodytube tree at the target site.
 98. The method of claim 1, wherein thebody tube tree is selected from the group consisting of a vascularsystem of the subject, a respiratory system of the subject, and aCSF-space of the subject.
 99. The method of claim 1, wherein causing theself-propelling bioelectromagnetic signal sensing device to travelwithin the body tube tree of the subject toward the target site includesat least one of causing the self-propelling bioelectromagnetic signalsensing device to travel within the body tube tree under the control ofa control system located at least in part on the self-propellingbioelectromagnetic signal sensing device or causing the self-propellingbioelectromagnetic signal sensing device to travel within the body tubetree under the control of a remote portion.
 100. The method of claim 1,wherein causing the self-propelling bioelectromagnetic signal sensingdevice to travel within the body tube tree of the subject toward thetarget site includes causing the self-propelling bioelectromagneticsignal sensing device to travel within the body tube tree toward a siteselected from the group consisting of a site located within a chamber ofa heart of the subject, a site located within a brain of the subject, asite located within a spinal canal of the subject, a site located withina gastrointestinal tract of the subject, a site located within aurogenital tract of the subject, and a site located within a musculatureof the subject.
 101. The method of claim 1, including at least one ofselecting a target site in proximity to a bioelectromagnetic signalsource, detecting the branch point with a sensor on the self-propellingbioelectromagnetic signal sensing device, or causing the self-propellingbioelectromagnetic signal sensing device to resume traveling.
 102. Themethod of claim 1, including engaging a wall of the body tube tree by atleast one of causing at least a portion of the self-propellingbioelectromagnetic signal sensing device to expand to form a pressurefit with a wall of the body tube tree, releasing an adhesive materialfrom the self-propelling bioelectromagnetic signal sensing device, orextending at least one claw or barb-like structure from theself-propelling bioelectromagnetic signal sensing device topenetratingly engage the wall of the body tube tree.